Cost Reduction Cards that let you play cards for less ink to play all say pay x less
Prosper, Tome-Bound Treasure and card-draw Tiefling warlock Prosper, Tome-Bound is a four-mana black and red 1/4 with Deathtouch that does a lot all on its own, but none of that is really combat-based
You get to essentially choose which you want as long as your opponents differ in hand size, which plays a bit into what Ms Bumbleflower is doing as the lead commander
It's an artifact, and plenty of cards care about artifacts entering, leaving, or being on the battlefield
Just as a little bonus, its ultimate ability is also pure value, giving you an emblem that turns the lands in your hand into flashback-versions of the spells in your graveyard, cause why not