Crucible of Worlds doesn't seem like an effect that could go for one mana.

Hmmm, the fact that it affects both players may make it ok.

Some other possible options:
Exotic Orchard type ability. (seems fun in the right set)
: Put 1/1 token (probably broken)
Lands you control have : Put this land on top of your library. If you do, search your library for a basic land card, reveal it, and put it onto the battlefield. Then shuffle your library." (Holy hell thats a lot of words)

Crucible is generally used in mana denial strategies, so making it symmetrical is pretty substantial.

@POSValkir
Orchard: I would need a bunch of off-color activations for that to be feasible. I had planned a few, but I don't think my set can support such a high amount.
Tokens: Probably? Most certainly. Players would just stop casting spells and mass Squirrel Nest each turn instead.
!Terramorphic: Word count is important, yeah. And it doesn't really differ much from the previous one I shot down. (It's also infinite landfall the way you worded it.)

Untap a permanent at the end of your turn.

Hey Mown! I made this for myself, but I thought you might be interested.