Even if youre playing a badly-supported typal deck like warlocks, giants, or something similar, these creatures grow your team, and they also work very well with changelings
Mister Fantastic The passive card draw on Mister Fantastic is already a great start, and the ability to double-copy a triggered ability has all sorts of uses, from infinite combos to strong value chains
My experience with colourless mana cards in cube is that you generally might as well splash a real colour, especially when it comes to things like cheap removal
Which one was your favorite
This will teach you which cards are crucial to the deck and which ones you can substitute based on personal preference
It's a very flavorful card, though a strange one mechanically, but that's what makes it fun to talk about