Laputan

Fork of (https://www.curseforge.com/minecraft/mc-mods/lilliputian) by cadaverous_queen (MIT license), a mod that allows random size variation for mobs.

• Changes size distribution to gaussian instead of uniform - this allows extreme variations in size to be more rare and rewarding to come across.
• Scales max health, movement speed, attack damage, knockback resistance, follow range and flying speed to size by configurable amounts.
• Allows additional random variation in these 6 stats by configurable percentage amounts.
• Accurate hitboxes for all mods and sizes.
• No visual "pop-in" effect for mob resizings.
• Highly optimized for performance and bug-free.

Unlike Lilliputian, the config allows you to configure the "sigma" value for each mod (instead of the range) which determines how much size variation the mob undergoes (defaults to 0. 0 which is no variation, I recommend 24. 0).

Works with all modded entities I tested except Ice & Fire's sea serpent, Fossils & Archeology's dinosaurs (mostly), and Frikinzi's Fauna. It is recommended to blacklist these.

See also (https://modrinth.com/mod/lecovian).