NPCs, items or adventure sites that you should be able to slot into your game. (But consider that some of my headcanon or fixes to official publications may have informed some of this.)
Bimbubbbudge and Whee: a friendly neighbourhood demon
I gave them stats but I really hope you don’t fight them
Three demon heads joined together, each of them with a potentially-crippling weakness to ordinary Ravenland materials, but they and their friend who can turn into a protective zorb work together. They joined up when realising how treacherous Ravenland was.
Gracenotes: ether, they live with an ent who’s interested in demon natural history, weaknesses aren’t all-or-nothing.
Gifts of the sea
Things that have washed up at Pelagia before Raven’s Purge
Gifts of the Sea should be in a sea cave, normally flooded except for rare tides.
Neyd’s staff, and the dwarf legend “the world was perfectly spherical” vs probable fact Neyd was annoyed with dwarves building mountains like engineers. A portal to the sea and all that can go wrong with something like that. Devices that will help you talk to underwater elves. Sacred tablets of Wyrm that don’t rust (heresy!).
Gracenotes: how many moons does your world have?, whiner stone, permanent delegation from Farhaven, don’t salt your neighbours land by accident, rubbish artifacts could have been snuck in.