Maybe someone's already done this math before, what's the most amount of cards played/powers used possible in a single hero's turn? For example if Argent Adept can give himself an additional power use with his play, and then give someone like Unity a card play which lets her give someone else a power use etc...
Assume ideal hero layout, hands, plateau but no particular environment or villain. What's the most number of powers and plays that you can get in a turn?
I suspect it may involve something like a fully set-up Adept with both Dynamic Siphons on him (from Captain Cosmic) which get deliberately plinked so the Adept gets to use powers to let other people do stuff, allowing someone else to activate something which lets Santa-Guise use his power to let someone else "unwrap all the presents" he's spent several turns giving them, which reveals something else that lets someone do something…like maybe the Adept plays an Arcane Cadence which chains through all four copies of itself…and then some other stuff happens. I bet the whole turn would be ridiculously complicated but amazingly epic at the same time, whatever happened :D.
If we're going theory, is there any reason (villain/environment, and time, put aside for now) why Santa Guise couldn't line up every card for every team member? 5 entire decks, all firing up at once (in, for the purposes of this experiment, an order of our choice)?
Santa Guise can only use his power for a single hero to reveal their cards once in a turn. He would not be able to do it for all five heroes in the same turn.
I'd say Santa Guise, Argent Adept, Captain Cosmic, The Scholar, and either Setback or Scientific Tachyon.
Not Unity? If she started her turn with Swiftbot in play, and used her two plays to give out two powers, that's a pretty solid start.
I hadn't considered Santa Guise. I feel like it'd be fair to take him off the table for the sake of this hypothetical.
Guise could also start the chain using I Can Do That Too! on his own turn or another turn through Super Ultra Kawaii!! or Selling Out to use either America's Greatest Legacy's power or Argent Adept's perform.
Ahh, my bad, I thought it revealed everything for everyone! Cheers for the clarification 
Setback playing "Turn of Events" with enough unlucky tokens will do better than this.
I can see K.N.Y.F.E. and her numerous on destruction effects allowing a lot of (pointless) plays, particularly with an equipment destroying environment card.
I tried AA, CC, Santa Guise, Scholar and Wraith; the answer is many. Like, I've exceeded a hundred and am not close to done yet. Unfortunately, I'm not close to done yet, and am kinda loathe to finish...
What if you just restrict to powers? That, at least, is a bounded amount.
EDIT: That is, how many powers can the hero team use during a single turn, given arbitrary set up? You can play as many cards as you want, but only power use counts. Since each instance of a power can be used at most once (almost always), there's an upper bound on the total. But maybe there are ways to do shenanigans like destroying cards with powers on them, then playing new instances of the same cards.
Yeah, card destruction shenanigans are all the rage. That said, it would still probably be less work...
Can you post what you had so far? I'm curious as to how it got to over 100!
Santa Guise himself can cause up to 40 cards to enter play in a turn.
Thus my suggestion to take him off the table for this hypothetical! He's just cray-zay.
Pro tip for powers: Plague Rat! His flip side gives everyone two extra powers they can potentially use, which may come in handy if you start running low on any given support character with all those Proverbs and Axioms you'll no doubt be playing.
My understanding is that Guise can't use Perform to play other people's songs. Is that untrue? But, if you use Greatest Legacy's power to make Argent Adept use a power…
The Argent Adept's powers says:
Activate a Perform text.Note that it says "a" rather than "your". So you could activate any perform text currently in play.