So there is this incredible game called Planetary Annihilation. One of the coolest games ever where you can smash planets into each other.
Some community devs took the source code and created an open-source game they're calling Beyond All Reason. The notable feature of it, is that it can support like 200+ players in collab.

I only mention it because anons here were asking what massive collab games Holo could play besides Minecraft and Rust.