"Cumulative upkeep [cost]" means "At the beginning of your upkeep, if this permanent is on the battlefield, put an age counter on this permanent
With that in mind, let's look at some of the best new(ish) equipment available to us for Galea or anything else
This was a banner year for precons, with six sets of four each, for a total of 24 decks
Sages Nouliths add nearly zero value to Yshtola, since it wont proc any of her effects and only really buff a small creature token
It also has built in card draw, though youll need some cards that tempt you to use it
If the target creature is an illegal target when Enter the Enigma tries to resolve, it won't resolve and none of its effects will happen