Chaos Zedruu (but trying to be reasonable about it)
Reasonable Chaos? Where I come from, we call that "Stax".
The first card I'd recommend is one I bring up fairly often!
Jailbreak gives you full control over what you do with it, it can ramp early by getting back a fetchland or bring back a Chaos piece late or give an opponent a piece back to deal with something bad. Since you have full control over it, it's almost never fully bad for you.
Spell Pod is pretty bad in practice, but given how many Chaos effects stop spells cast from hand and do not care what happens to them before replacing them, you can pod them to get something else cast from Exile that won't get Possibility Stormed or Knowledge Pooled or what have you, while still getting the extra spell with those.
You can also use it as a threat: Cast something from your hand that might be awful for some other player to deal with, and ask for a favor if you pod it instead, though without offering guarantees that whatever else you'd spin into won't be worse.
Observed Stasis is a pretty great Commander removal in general. It draws usually one or two cards, and removing all abilities plus ability to block of a commander will cripple plenty of decks. It's instant speed, can mess up a combat, and in Zedruu it's one of those removals you can them give away to somebody else to trigger Zedruu a bit more. As long as you don't give it to the person you've enchanted the commander of, the "Enchant creature an opponent controls" part is still valid. Though being able to give it to the person to free their commander at any time is also something you can negotiate with!
In general, since so much of Chaos ends up with spells being cast from exile, a package of support for exile and casting spells from there could help the game actually end at some point, plenty of other options than these two, as Prosper decks prove.
Targeted swap removal used in its intended way is also a way to do Chaos that isn't nearly as obnoxious on a table. Notably, with the ones of these that refer to the permanent's OWNER, you can use them to rescind gifts you gave with Zedruu if someone is being mean with them, and you get the benefit. Are these great removal? Certainly not, but they are chaotic and feel better about it.
