Automated Evocations - jbowensii/FOUNDRYVTT-DnD5e-Base-Game-Configuration GitHub Wiki
Automated Evocations Companion Manager
A user interface to manage companions with summoning animations and automated summoning for spells
https://foundryvtt.com/packages/automated-evocations
So if you have a summoner in your game this module is a must. I did select to store companions on the actor and not the player, since sometimes my players are absent and another player will run two characters but only be logged in as themselves. I also restrict to only the companions that I have pre-setup ownership with (don't forget to change the hostility).