Food Chain and Concordant Crossroads on the battlefield.
({2} magic symbol) ({G} magic symbol) ({U} magic symbol) plus enough mana to pay for commander tax, if applicable available.
Steps
Cast Jyoti from the command zone by paying ({2} magic symbol) ({G} magic symbol) ({U} magic symbol) plus commander tax, if applicable.
When Jyoti enters the battlefield, its first ability triggers, creating a 1/1 Forest Dryad creature token for each time you've cast Jyoti from the command zone this game.
Activate a Forest Dryad by tapping it, adding ({G} magic symbol) .
Repeat steps 3 for each Forest Dryad token created in step 2.
Activate Food Chain by exiling Jyoti, adding ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) that can only be spent to cast creature spells.
Choose to return Jyoti from exile to the command zone.
Activate Food Chain by exiling a Forest Dryad token, adding ({U} magic symbol) that can only be spent to cast creature spells.
Repeat step 8 for each remaining Forest Dryad token.
Repeat from step 1.
Once you have infinite mana, you may forego exiling or tapping the Forest Dryads.
Results
Infinite colored mana that can only be spent to cast creature spells.