Selective Peaceful Mobs

Once a player turns on the peaceful setting, hostile mobs pass by that player unless it is attacked. A mob that is attacked retaliates for a limited time, and the setting applies per player, so one player can be ignored by a mob that still targets another. Direct attacks and player-fired projectiles both trigger this retaliation, and an optional group aggro setting can pull nearby mobs of the same type into the fight within a configurable radius.

Players manage their own choice, while operators can inspect it or reset another player's setting with admin commands that require permission level 2 or higher. The setting survives moves between dimensions, logging back in and server restarts. The server owner sets the default for new players in the generated configuration file and can change the list of mobs allowed to target players, the difficulty rules and spawning rules. The Ender Dragon, Warden and Wither stay hostile by default.

The mod is a NeoForge build for Minecraft 1.21.1 and runs on the server alone, so players join without installing anything. The code is open source under the MIT License.