Dredge decks use the dredge mechanic to quickly fill up the graveyard
It takes a little while to transform Sidequest: Hunt the Mark into Yiazmat, Ultimate Mark, but you do get a removal spell up front, and it costs nothing to get your free Treasures
Some of them see occasional play in Standard and/or Explorer and Pioneer, but they have been pulled back enough not to make them overwhelming, but at the same time they are in some cases in a poor place where they are overly strong in limited, but dont do anything in constructed
Grouphug decks will love this, and depending on the metagame of your Commander and cEDH pod alike, Tataru Taru can appear anywhere since its just two mana
If you cast a card without paying its mana cost," you cant pay any alternative costs such as emerge costs
While I could see this getting a bit out of hand if too many creatures were printed like this, I do like the idea when its limited to just a few