Been playing with card designs, mainly for Modern/Pioneer, and came up with a card that might be good across the board, but not particularly broken (I don't think).
https://mtgcardsmith.com/view/mana-incubator
My main concept was to design a card that could ramp to 4 mana on turn 2 in Pioneer, but would come at the expense of being vulnerable and costing your turn 1 without being reusable. It would also be useless in tron builds in modern, mostly, as it needs colored mana to cast and takes up the time needed for turn 1 map/stirrings.
Thoughts?