https://www.reddit.com/r/dndnext/comments/b4k3p6/dd_swarm_simulator/
Someone made a site for auto-calculating damage calculations for large groups of creatures: https://oganm.com/shiny/swarm/
"This is a tool to automate damage calculations for large number of creatures. You give the target AC, number of creatures attacking, and attack statistics, it returns the damage dealt to the target by rolling the dice. You can also select an SRD monster's attack or an "Animate Objects" object size so fields can be filled automatically. That SRD monster selection box allows for searching so no need to …