Time vault

[Iandtormentor]

Turn 1: {swamp} {Lotus Petal}  {Dark Ritual}  {Time Vault}  {Voltaic Key} activate the key with the  {Lotus Petal} to untap  {Time Vault} tap {Time Vault} to give you 1 more turn on you next turn activate the key to untap {Time Vault} tap {Time Vault} for 1 more turn ect.

[Deathseide]

Turn 1: {swamp} {Lotus Petal}  {Dark Ritual}  {Time Vault}  {Voltaic Key} activate the key with the  {Lotus Petal} to untap  {Time Vault} tap {Time Vault} to give you 1 more turn on you next turn activate the key to untap {Time Vault} tap {Time Vault} for 1 more turn ect.

{swamp}, {dark ritual}x3, {panoptic mirror}, {time walk}
No need to do any tapping or untapping with this one... And you have the extra 2 mana free each turn

[Iandtormentor]

A 6 card combo is a pretty hard combo to pull of

[Fenster]

Both are difficult to pull off.
Way too difficult to be efficient

[Leonidus78]

Time vault has already made an appearance in legacy many times with tezzeret as both enabler and untaper.