there are a number of cards that reward you with token creatures whenever you cast spells
Assuming youre not going to try proliferate shenanigans, you can also try Tyrite Sanctum, although thatll take a little time
This was another problem we could solve while finding the replacement
Creature - Sphinx Draw (CTRL to add secondary) Enchantment Magmatic Core Cumulative upkeep (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.) At the beginning of your end step, this enchantment deals X damage divided as you choose among any number of target creatures, where X is the number of age counters on it
Although paying mana is the most common and is the typical cost, there have been a number of innovations
Charizard V SWSH050, SWSH Promo Series