These are some basic, bare-bones ideas or thoughts.
1.
A Bond of Choice: In the Kingdom of Humans, dragons dwell and live among them freely as citizens- often taking human shape to blend in among the masses. While a common villager may have a dragon for a best friend, only the nobles and royalty have dragons bound to them by an age-old magic.
Extra: I actually have some ideas for this one!
2.
Afterfall: Due to a natural disaster, the entire world has been left devastated by mutation and corruption. Most people have turned into monsters and lost their minds while others have gained powers and have begun to adapt to the new changes in the world.
Extra: This one has potential for a lot of world building.
3.
The Monster Next Door: In the modern age, the supernatural and fantasy creatures have long since joined society. Its common to see vampires working night shifts, to see faeries floating around in parks, etc. Due to circumstances, a human ends up getting an apartment in a 'monster only' building.
Extra: I imagine this will have a lot of characters and probably multiple pairings.
4.
Again and Again: After the loss of their soulmate, Character A is decidedly not looking for anyone anytime soon- if ever. In comes crashing Character B who doesn't have a soulmate but is eagerly looking for more friends. Their first few meetings are a bit disastrous but CB is determined to help CA, be it for their own personal reasons or otherwise.
Extra: Up for easy editing to be more accommodating for other ideas. I just like the idea of a character trying to save someone else while they themselves are also sinking.