Orvar, the All-Form | Great Whale | Imps' Taunt

Cards

Imps' Taunt in hand.
Orvar and
Great Whale on the battlefield.
You control up to seven lands that can tap to produce at least ({4} magic symbol) ({B} magic symbol) .

Activate up to seven lands you control by tapping them, adding at least ({4} magic symbol) ({B} magic symbol) .
Cast
Imps' Taunt with buyback by paying ({4} magic symbol) ({B} magic symbol) , targeting
Great Whale.
Orvar's first ability triggers, creating a token copy of
Great Whale.
When the
Great Whale token enters the battlefield, it triggers, untapping up to seven lands.
Resolve
Imps' Taunt, returning it to your hand.
Repeat.
If you control up to seven lands that can tap to produce at least ({5} magic symbol) ({B} magic symbol) , this combo nets infinite mana, which you can then target any creatures you control in step 2 to create infinite token copies of them.