If a card says counter a spell, draw a card, bounce a thing, steal a thing, do some damage or is some kind of tempo board play and it is in a cube the chance are that the card will be OK
Starving Revenant needs a steep 8 permanents descended into in your graveyard and does a consistent life drain, but they both fall below Sheoldred, the Apocalypse
Cards like Boseiju, Who Endures, Arena of Glory, and Cori Mountain Monastery fulfill a similar role to MDFCs in that they provide a land with an additional or alternative mode so that you still have a way to spend your mana, even if you draw a bunch of lands
In case you haven't seen them before, here's a quick look at some of their peculiarities
But only one or two fit into decks I play