She works especially well in go-wide token builds that want to pressure early while preparing recursion lines
Lets go through the facts first, or at least what we know so far
In a deck built to leverage creatures dying, Tombstone Stairwell should be able to really put in work if I've got even a decent number of creatures in the graveyard
Iconic Cards: Counterspell, Ponder, Damnation, Jace, the Mind Sculptor Popular Decks: UW Control, Jeskai Control, Taking Turns, Esper Control 3 Midrange Midrange decks are popularly said to solve problems, not create them. In other words, these decks are sort of designed to be able to win against every archetype, although they wont bulldoze over anything (the way aggro often wrecks control, for example)
Your best bet is to focus on meta cards like the EDREC top 100, and anything commanding a high price is worth a closer look
Its important to become familiar with your cards, obtain the necessary ones for your deck, practice regularly, and seek guidance from more seasoned players.