I've seen multiple mentions on forums and in YouTube videos that a player can only 'use' a single villager per round. However, I don't see anything about this in the rulebook. All it says about using villagers is:
Seek Aid: You may move a Villager with the Aid term on its description from Town Square to the Town Discard to gain its effect.
Example: An attacking hero may pay 1 Coin and discard the Smith to add +1 damage to their attack.
The epic actions, which are only allowed once per round, are explicitly called out.