I did some fiddling around with my Talrand and Proteus Staff, I found that I preferred it to Polymorph because I could throw a Sphinx of the Second Sun in, and if Proteus Staff hits Sphinx first it's amazing because I get to untap and draw an extra card before I hit my end step, meaning I can likely Staff again to get Jin just in time (and still have mana up for interaction). I guess it boiled down to me trying to raise the ceiling on Jin, and that was the best I could come up with! The other nice thing about an artifact plan is Blue has tons of relevant tutors, and if you clear all of the creatures out of your deck and Proteus Staff away another Drake you get to put your library in whatever order you want... meaning Jin can then draw you the actual 7 cards you want most. It's very, very degenerate when it works, but I was aiming for a budget cEDH list rather than something suitable for casual play.

I'm not sure if you need blockers, but Metallurgic Summonings can generate a bunch of them for you, and Shark Typhoon can generate attackers (or flying blockers if you're desperate), they're handy if your playgroup likes to 'deal with' Talrand, these Enchantments tend to be very sticky, people neglect Enchantment removal in my experience.

If you're aiming for a more casual Talrand, I might have a few ideas for you that are budget to boot! Hands of Binding and Hidden Strings offer two very low to the ground repeatable spells that can generate Drakes if you can Cipher them onto something evasive and get in, Hidden Strings can untap your stuff fwiw, and Hands of Binding can lock down the most problematic thing if you want. Last Thoughts isn't as good IMHO, but repeated card draw tends to be very good if you don't need to input more resources. Stolen Identity can be a solid win con, if what you take has evasion you can keep getting in and getting copies, it can get pretty out of hand, even as a 6 MV spell.

If you like politics and/or combat tricks I might have a few that are worth looking into, Mass Diminish is a true budget gem, the effect lasts long enough to be truly crippling late game, and it has Flashback for no discernable reason, very good at making one opponent dead, and then another opponent dead because their board is tiny. Polymorphist's Jest is much more of a surprise since it's an instant, but the effect can turn an opportunistic attack into a bloodbath (in either direction).

In any deck that's not in the ideal colours for removal I often end up looking hard at Transmogrifying Wand, this can deal with 3 creatures if it sticks around, 2/4s are basically trash vs your 2/2s in the air. Even if all you do is force someone with a low MV Commander to keep recasting to raise the tax it's very little resources to do it.

It's not a nice thing to do to someone, but I've always thought of Talrand as a real man of culture, perhaps you'd want to send some Drakes on a Cultural Exchange?

Best of luck, hope some of these ideas are relevant

Neat idea, I love seeing people making Gruul work in Legacy!

I would run two more Utopia Sprawls over Rampant Growth, they aren't all that pricey anymore (ymmv of course). I'd even run a worse Utopia Sprawl like Blighted Burgeoning or Fertile Ground, either has it's own upsides, and both work very well with your Arbor Elf.

I think with x4 Arboreal Grazer you might consider at least a couple lands, Grazer feels awful when you're short of lands. I'm not sure how much you'd need, but 1 or 2 would be helpful IMHO.

Randomly, Gruul got one of the all time great ramp effects back in Ice Age, Orcish Lumberjack is epic ramp, great if you need to hit a Hulk several turns early. You might want something to prevent your Hulk from getting countered, maybe Rhythm of the Wild? The haste is also VERY good with Lumberjack, letting you drop it and tap it for 3 (though you do sacrifice the Forest) right away, dodging removal potentially. I personally love using Orcish Lumberjack with Mwonvuli Acid-Moss, this way you can effectively Sinkhole people in Gruul, and technically you'd have 1 mana left, even on turn 2. Some people don't fear land destruction and will keep a 1 land hand so it can work sometimes fwiw, and the cost is negligible (it's even a ramp spell if you hard cast it without Lumberjack).

How often do you end up with a decent land count? If you find you can actually hit 5 lands in a lot of games, you could throw in Crop Rotation and Temple of the False God x1, if you aren't ready for a Temple yet you can tutor up a Red source I guess, or a Wolf Run. I'd guess if you pull those Rampant Growths Temple x1 isn't worth bothering with. You could always do that trick with x1 Ancient Tomb, but those aren't as cheap!

I sometimes wonder if Spurnmage Advocate could ever find a home, but seeing this deck makes me wonder if it might fit in here as a deterrent of attackers that can be sacrificed to counter something if you're desperate, it's only W to cast and the downside interacts incredibly well with your Stax effects. For example, if you have Rule of Law out, you can usually give people things like Ponder, as long as they are Sorceries they are almost worthless, if you have an effect that makes lands enter tapped you can give them Fetchlands with a smile. Other Stax/Hatebears let you pick other cards as situationally bad. Another upside of Rule of Law + Advocate is the opponent can't flood the board easily, making the deterrent more effective over time. This advocate is also good with your Drumbellower, especially since it doesn't use extra mana to activate it's ability.

Have you considered tossing Zur the Enchanter in here? You have quite a few small enchantments (18? I run Zur in a deck that can find about 12 cards, and he's an all-star in there), so if you resolve him it could feel pretty good.

Do people play a lot of interaction in your meta? If so I really love having Wandering Archaic  ^Flip out with Rule of Law, it makes it interaction a lot worse vs you, and much better vs most of your opponents.

I'm going to have to fiddle around with your list at some point, I've wondered how effective a competitive deck this Ertai would make, the effect is very strong, and the colours are strong enough, I guess Zur just caught my eye first and I built that way back, and cEDH lists are pricey! Anyways, cool deck idea, hopefully you can keep it updated/polish it up as you notice issues.

I have Diabolic Revelation in one deck atm, it's purpose in that deck is to generate card advantage, usually for the next turn. In that role I find the card quite satisfactory, and I wouldn't be as happy with a Rune-Scarred Demon because it doesn't generate card advantage the same way, and the body created probably wouldn't be impactful enough for the mana. I think if you have reanimation or flicker effects then the Demon will almost certainly play better. TBH I don't think either card is a 'good' card, but either can provide a high cost tutor effect (which is desirable in certain metas), one can provide significant card advantage while the other is stapled to a 6/6 flying body. If you ever find yourself wanting to cast Revelation where X < 3 I would cut it, Diabolic Tutor is actively clowned on, and Revelation is much worse Diabolic Tutor if X = 1. I think the nicest utility for the Demon is actually that you can use it as a blocker to hopefully last until your next turn (so you can win), casting Revelation will attract even more attention while providing no blockers.

Any reason you don't use Brash Taunter? It's great with damage based wipes, suddenly your Blasphemous Act family spells also dome an opponent, if you can double that you'll probably eliminate someone.

In a list that has a decent number of creatures that can deal damage you might look into Basilisk Collar, it's good with many of your creatures, similarly Scavenged Brawler can turn a mediocre creature into a real problem. I'll never forget putting those counters onto a Brash Taunter!

It's probably not the best thing you can be doing, but Crypt Rats and similar effects are endless fun. There is also Exocrine, this weird guy can generate a lot of damage if you've got the mana, yet it also will draw you a card and leave a huge creature. Also, what the heck, Thrashing Wumpus exists too, and can Pestilence twice every turn without croaking, which could add up/cripple your opponents' boards. Very good if you've got Whip out obviously!

Do people run a lot of Blue in your meta? I liked Citadel of Pain a bit in a deck like this, normally this is symmetrical, but with your synergy it might play a lot better. I like Citadel in decks that feature a fairly high MV, where you don't want people to be able to bluff by holding up mana.

Since you don't run a ton of lands, maybe Acidic Soil? That could be 3 mana to win on the spot in some games.

Would Descent into Avernus work in here? It'll speed up games, not sure if your deck is usually one of the faster ones in your pod, if so it should help, if you're normally a slower deck then it's probably going to get you killed.

Fires of Mount Doom is a dual purpose card, offering you a way to slow down a Voltron deck, yet also a way to draw cards. I normally wouldn't bother with Impulse draw, but if your deck isn't really into combos then it plays well enough. Another nifty way to get cards in hand that opponents probably can't take advantage of with Obosh out is Wheel of Misfortune, a card I normally don't like. If you can double that damage (or better), then opponents will be very wary of trying to wheel.

Kaweiwu not quite sure what you mean by that, Keen Duelist punishes your opponent for your high MVs, and punishes you if your opponent has high ones too. It's very different than Dark Confidant type effects.

No Reassembling Skeleton? What about something like Sengir Autocrat, make a bunch of bodies to generate maximum triggers? Gixian Puppeteer seems like a good fit. I feel like Dreadhorde Invasion might be good with your Commander, as long as you sacrifice the token you get a fresh one on your upkeep, this is a relatively affordable alternative to Bitterblossom. If you like the Underworld Dreams effect, perhaps Fate Unraveler, though it's not exactly budget at this point and will surely go down in price if it sees reprint, so maybe keep an eye on it? I feel like your deck would benefit from anything that prevents life gain, stuff like Grima Wormtongue and/or Knight of Dusk's Shadow might keep opponents from running away from your damage/life loss effects, and Plague Drone actually punishes opponents for trying to gain life.

Well, after a quick search I found a few damage spells that might be worth checking out: Mine Collapse can deal 5 damage for no mana in a pinch, if this can kill an opponent at a good moment it could definitely be worth it, Spire Barrage/Spitting Earth can each hit a single creature for potentially a lot (spreading it out sounds incredible to me!). Their is also Jaws of Stone if you really, really like the effect.Transmogrifying Wand is an incredible piece of removal in a mono-colour deck.

What kind of help are you specifically hoping for?

I didn't want to spam your deck with a link to mine, but I thought you might want to see my Sisay list anyways. Lots of cards in common between the two decks, but enough difference that it might be worth taking a look! I'm still brewing the list, but it's a relatively fun that I can be played vs a wide range of decks, if opponents aren't playing at a high level I just dig out Shrines and cards that synergize with them, if they're playing competitive Magic then I just go right for infinite WUBRG to win on the spot.

Madam Sisay's Illustrious House of Fine Shrining

I'm not sure if you should be running that many guild Signets, why not just run more Green ramp that is better at fixing your mana? Artifacts do better in cEDH than more casual games, but you'll be feeding Dockside. I'd even run Talismans over Signets if you feel desperate for 2 mana rocks, Talisman of Indulgence is a more useful card in most situations than Rakdos Signet. Also Fellwar Stone exists fwiw.

Similarly, I'm not sure if you should run ETB tapped Fetches in a cEDH deck, but I will admit the fixing is nice. Stuff like Rocky Tar Pit belong in more casual games, at least in my experience.

I can see you have tons of combos in here, but I can't help but mention Selvala, Heart of the Wilds, she synergizes incredibly well with Sisay, Emiel and a Haste source (like Samut), usually netting you infinite mana and as many cards as you want (by flickering your Sisay, who should be the strongest creature). I only mention it because I think you've got everything Selvala needs to work, and she's a Legendary mana dork that can make any colours of mana.

If you're hoping to play cEDH I would recommend you run at least a couple Counters, some relatively affordable ones (that still hit relevant stuff reliably) are Swan Song, An Offer You Can't Refuse, and maybe Pact of Negation or even Flusterstorm. If these are too pricey you can also try Arcane Denial or Dispel. I would definitely run Dispel over Lightning Greaves in a deck like this, people don't run Sorcery speed answers very often in cEDH, so they'll just wait until you're going to equip the Greaves and then Swords you.

Do you have a plan for Opposition Agent? I feel like if people resolve one you're going to be having a very bad time, unless I'm missing a bunch of removal, and people love Oppo in cEDH. You might consider some of the more versatile removal options, stuff like Generous Gift, Stroke of Midnight, and Beast Within can hit pretty near anything you need gone.

I'm also of the opinion that a few more lands would probably solid, 31 doesn't feel like very many, a few more would probably help with consistency (which may or may not be an issue for you).

It might not matter as much if you play vs other casual decks (you'll be less likely to be punished for running artifacts), but in Selesnya I feel like you don't want mana rocks, Green has access to some really good ramp effects, and they're often fairly affordable. For example, I think I'd switch out Arcane Signet for Rampant Growth, Commander Sphere for Kodama's Reach, Cluestone could go for Harrow (if people counter ramp spells I'd go with Roiling Regrowth instead), and Sol Ring could go for something like Wild Growth/Utopia Sprawl/Crop Rotation. If you go this route I would consider switching a few Plains for Forests, even if your deck ends up having a lot of White effects, Green ramp can find Plains for you.

When I try to build Casual decks, I still try to put removal in, but I try not to run stuff like Swords to Plowshares, and instead try to use less pushed options like Intrepid Hero, Avenger en-Dal, and Spurnmage Advocate. Each has it's own drawbacks, but the fact that you can't 'catch' (they aren't a 1 mana Instant) someone with these makes them fun in my experience. Spurnmage is a really powerful political card that can be helpful vs graveyard decks, and Avenger can technically gain you life if you have a big creature and just want the life, but it's also a deterrent. If you want a non-creature source of creature removal their is also Transmogrifying Wand, this is one of the best 'lower power' removal effects ever printed, it's good enough to make a big impact once resolved, but you need it to stick around to get full value over time. IMHO there's nothing wrong with running relatively little removal in a casual environment, but you'll probably win a few more games if you have some ways to slow down opponents that happened to draw well, so if that matters you might throw a few things in.

Not sure if you want actual jank, but Noble Purpose is an old favorite of mine that gains you tons of life if you're in combat, but most importantly it fully stacks with Lifelink.

Urza's Saga might be useful, it can find MV 0 or 1 equipment, and it can also make chump blockers for you which Arden can equip in a pinch.