phoenix cards mtg Heart block) element.class Nemesis Phoenix (CLB-189) - Commander

On paper, it seems pretty balanced and self-restricting, for sure there won't be any oppressive card with this ability

Sacrifice it at the beginning of the next end step if it has mana value 3 or less

Marchesa, the Black Rose : When I build Marchesa decks, I use plenty of creatures that naturally enter the battlefield with +1/+1 counters, which means that, with Marchesa, the Black Rose on the battlefield, we can feed one to emerge without going down a card

You can do this to draw a card after your mana is set or in response to the massive recursion and graveyard (ab)use at the Commander table

Again, it depends on your environment how deep you go with sideboard cards