Outside of decks that use Lurrus of the Dream-Den, Elspeth Conquers Death should be a control staple in all decks that maximize its effects
This means that this new take on amass is backwards compatible, and will work with the older, Zombie-centric ones from Nicol Bolas invasion of Ravnica, far far away from Middle-earth
Strong Even on its Own
While the additional Kicker can only be paid while casting a spell, Power-up can be paid when you cast the creature (at a reduced cost) or later on for more mana
There are a ton of common creatures that cost the same as the energy they bring with them on ETB, and a few, like Minister of Inquiries, that bring more
Any version of the Pokmon from Genetic Apex will work, however, whether it's an ex or alternative art or regular or whatever else