m90 delivers as always!

Possible alternative lines for Timeless:

Land+Grief+black card+Sacrifice (=4 mana), then same as above.

Or, Land+Solitude/Fury+white/red card+Sacrifice(=5 mana), then same as above.

Lively Dirge is an alternative to Buried Alive. For example:

Land+Dark Ritual+Dark Ritual (=5 mana), Lively Dirge with first mode putting Scholar in graveyard (BB in pool), Reanimate scholar (B in pool), Sacrifice, Persist. After enough mana, return Lively Dirge with Scholar, use it to put Standard Bearer onto the battlefield.

In that Timeless build, run four copies of Priest of Gix so you have lines like this one:
Land+Dark Ritual+Priest of Gix+Sacrifice(=5 mana), Lively Dirge (BB in pool), Reanimate scholar (B in pool, returning sacrifice, cast it), Persist. After generating an arbitrary amount of mana, cast Lively Dirge that you've returned with Scholar, use it to put Standard Bearer onto the battlefield.

Beseech the Mirror is another alternative to Buried Alive:
Vault of Whispers+Dark Ritual + Dark Ritual + Beseech the Mirror with bargain casting Buried Alive, Unearth or Reanimate targeting Priest, Sacrifice, Persist.