I’m running a campaign set in the feywild and my lvl 10 players have just entered the feydark in order to stop a fomorian invasion. I’m looking for some ideas for random encounters and for creatures that would be enslaved by fomorians. Anything would be helpful, thanks in advance!

A few months back my players entered the feydark. here’s a few encounters I did:

- deep dragons (or reflavor any dragon to look more fey)

- a few giant crocodiles

- some trolls

-fomorians (also some trollocs)

- reflavored some demons (mostly bulzeau’s and vrocks)

- a lot of weird plants

- willowisps

Im not to familiar with the fomorians intelligence, but I feel like it could easily enslave less intelligent beings like crocodiles, snakes, wolves beastly kind of things. Some of the other things I mentioned might not work, but have fun! The feydark was wild, and my players and I had a ton of fun

Tradionally:

Spriggans, gnomes, myconoids, and Chitine lived in the Feydark. Spriggans have not been updated to 5e. They were descendents of gnomes, but had stats like sprites but looked more like ugly goblins.

Drow tended to invade it.

Also, drakes, stirgers, hooked horrors, shambling mounds, trogolytes and vine horrors were found there.

the thing I thought of were nothics. a bit out there but look at the formoian art's eye and the nothics art's eye. they look so similar, so maybe you could incorporate nothics with the blessing of the king who crawls to beef them up and throw them at the pcs

The fey dark seems to be about vibrant colours and glowing lights

• Pixies using dancing lights pretending to be a large bio luminescent monster in the dark, possibly a umber hulk
• An actual umber hulk
• Beasts with glowing patterns like a glowing wolf 
• Luminol red caps that make blood glow. On a hit they have an effect similar to fairy fire.

I also think story references work well for the fey wild and in the fey dark you will want things doing with caves and darkness

• A shape shifting wizard magically imprisoned in a cave  by his ex student who he  is obsessed with. If there is a wizard in the party he will teach them a spell if they answer a riddle.  ( this is a reference to a story about merlin).
• A young fey boy named Edmund trying to pick a locked door  if they help them open it there is an angry cockatrice on the other side.  ( just a random fairy tail called edmund and the cockatrice I found on google) 
• A cave with dripping water that turns things to stone.  Walking through the water has the effects of flesh to stone with a low dc, if players have a way to safely collect a vial of the water they can throw it at enemies as an action. (A reference to mother shipton's cave)
• A cave under the effect of the spells [Tooltip Not Found] that contains the sleeping  beautiful sleeping Endymion. If they awaken  him by either  dispelling the magic on the cave, bumping in to him in the dark or trying to remove him then he rapidly ages upon leaving the cave.

This is awesome guys thank you so much!