OK this one is an early idea whether its anywhere near balanced as is I have no clue.

Heh. City of Shadows meets Black Lotus. Except it's a bit more repeatable, although only with tokens or undying creatures or similar. It's a better rate of return than Thermopod or Ashnod's Altar, that's for sure. But it's only once a turn, and the earliest it can give mana is turn 2 and then only if you sac a one-drop. So it's not "auto-include in every deck". It does give you a 5-drop on turn 2 or a 6-drop on turn 3 for a little card disadvantage, so it'd certainly be played in tournaments.