Walled Garden MRF
This allows someone to create an instance that does one-sided federation; that is, others can see the posts on it, but not the other way around. One noteworthy instance that has this is brighteon.social. I used this to try to run a Werewolf: the Forsaken, 2e game over the fediverse, and I used this to stop people from heckling the players. However, not enough players showed up and it was eventually was terminated. You can see our progress on howlsoverelpaso.xyz.