They must usually be Set on the field, and may be activated at any time after the turn they were, including during an opponent's turn
guywitharock on These aren't Homemade, They're made in bombfactory 1 year ago You may want to consider some "mana dorks" for your commander in the way of easy-to-cast, different colored token creatures: Also, there are some interaction-related convoke spells which are probably worth subbing in over other non-convoke options: Depending on the direction you want to take, there are some cards which support a swarm strategy: Nadir Kraken pairs nicely with your extra card draw, and generates rare blue creature tokens for blue-color convoke mana
Scurry of GremlinsScurry of Gremlins (3,366 Inclusions, 1% of 517,635 Decks) Now this is what I'm talking about
You could even add Loot, Exuberant Explorer or Hugs, Grisly Guardian for extra land drops and card advantage