It has, to name a few, Modular, Affinity, Madness, Storm, Delirium, Suspend and Converge, among others
Charizard GX SSR and Umbreon GX SSR drive demand
The Ult is unlikely to ever happen (as you are most likely going to minus 4 or something when you play him), but if it does occur, the quality of the 7 permanents being put on the battlefield will generally be high enough to win the game
You can just tap all your creatures at your opponent's end-step and deal direct damage
1998 Brian Seldens 1998 World Champion deck is a combo deck making use of Survival of the Fittest and Recurring Nightmare to tutor up creatures, put them in the graveyard, then sneak them into play