They are incredibly rare as they themselves are basically bosses. If ur curious about where they can be found if you wanna try and grind out their spawns, they're found on Monster Island on the Island, the mountains in Scorched Earth, the Element Chamber in Aberration, and the volcanic areas on center/ragnarok.

how would one go about increasing their spawn rate?

DinoSpawnWeightMultipliers=(DinoNameTag= (TAGNAME).
SpawnWeightMultiplier=10.0,
OverrideSpawnLimitPercentage=true,
SpawnLimitPercentage=0.015)


i understand this is one line but what would their tag names be?

where is the saddle for the rex's i cant find them anywhere

The regular Rex saddles should be a-okay for the Fulgar versions. Same with the Carnotaurus. At least I believe it should be.