For infinite mana, ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) is required, and your opponents must have at least 3 artifacts and/or enchantments.
For infinite creature tokens and mana, ({5} magic symbol) ({R} magic symbol) ({R} magic symbol) is required, and your opponents must have at least 4 artifacts and/or enchantments.
Steps
Cast
Dockside Extortionist for ({1} magic symbol) ({R} magic symbol) .
If you want infinite creature tokens, skip to step 8; otherwise, continue to step 3.
Dockside Extortionist ETBs, putting its ETB trigger onto the stack.
Tap
Lithoform Engine, copying the ETB and triggering
Kurkesh.
Pay ({R} magic symbol) for the
Kurkesh, copying the ETB an additional time.
Resolve both copied ETBs, generating at least 6 treasures.
Continue from step 11.
While
Dockside Extortionist is still on the stack, tap
Lithoform Engine for ({4} magic symbol) to copy
Dockside Extortionist, triggering
Kurkesh.
Pay ({R} magic symbol) for the
Kurkesh trigger, copying
Dockside Extortionist an additional time.
Resolve both
Dockside Extortionist copies, creating at least 8 treasure tokens.
Tap
Voltaic Key for 1 treasure token, untapping
Lithoform Engine and triggering
Kurkesh.
Spend 1 treasure token to pay for the trigger, copying the untap ability targeting
Voltaic Key.
Repeat for infinite treasure tokens, and creature tokens if applicable.
Results
Infinite colored mana.
Infinite creature tokens.
Infinite ETB.
Infinite sacrifice triggers.
Metadata
In 9 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Not Legal (Bracket N/A).