While adding the fomor scroll hunting quests, I've noticed a few unused fomor scrolls, which give us options for custom content, either by implementing the quests they were intended for, and their monsters, or by replacing them for custom ones. Namely, the unused ones are:
71014: Gray Dire Wolf Fomor Scroll
71020: Giant Spider Fomor Scroll
71024: White Fox Fomor Scroll
71027: Black Bear Fomor Scroll
71033: Giant Rat Fomor Scroll
71036: Golem Fomor Scroll
71046: Black City Rat Fomor Scroll
71048: Boar Fomor Scroll
71053: Giant Worm Fomor Scroll
71054: Gargoyle Fomor Scroll
71071: Dungeon Rat Fomor Scroll
Some are monsters I didn't know yet, and 2 are bosses, which I find really intriguing. I also wonder why they didn't add Giant Worm and Gargoyles. Especially Gargoyles are monsters you encounter very frequently in early generations after all.