Savaru Mob Control is a lightweight Fabric 1.21.1 server-side behavior mod for controlling when monsters are allowed to target players.
By default, affected mobs will not actively attack players on sight. They stay passive toward players until a player damages them first, at which point that specific mob can retaliate against that attacker for a configurable amount of time.
The mod is built for modpack control and includes multiple ways to decide which mobs are affected. You can use blacklist mode to control almost every mob except selected exceptions, or whitelist mode to affect only selected mobs. Entity type lists, datapack entity type tags, and vanilla-style command tags are all supported.
Dungeonology and Worldology integration is optional and can be toggled. Dungeonology run mobs can keep their normal dungeon aggression, while Worldology Lord and Ruler tier gameplay can bypass the passive-mob behavior so high-level world progression remains dangerous.
mobcontrol:blacklist and mobcontrol:whitelist./mobcontrol status
/mobcontrol enable
/mobcontrol disable
/mobcontrol mode blacklist
/mobcontrol mode whitelist
/mobcontrol whitelist add minecraft:zombie
/mobcontrol blacklist add minecraft:warden
/mobcontrol tag whitelist @e[type=minecraft:zombie,sort=nearest,limit=1]
/mobcontrol tag blacklist @e[type=minecraft:warden,sort=nearest,limit=1]
/mobcontrol compat dungeonology on
/mobcontrol compat worldology on
/mobcontrol reload