(sorry for bad english)
Abandoned
Abadoned guy in post apocalyptic world? (maybe city – like silent hill)
Adapt to Survive
Game about bio or biomechanic things crafting upgrades to another levels (like fish lungs or grashopper legs)
Among the Stars
Just exeperimental space game! (aether was nice). Or space variation of pixel dungeon.
An Unconventional Weapon
Well… I watched lots of anime so… This one will be easy XD Maybe some kind of nes styled platformer with weird guns. (bioweapons or just mecha-poop or flying soy sauce)
Companion
Something like three wikings. Art and story driven.
Creatures of the Night
HORRROOOOR! Something like film THE BIRDS but with creatures. Day – upgrading home base. Night – Fight with creatures.
Day and Night
This can be same thing like creatures of the night. OR Some game about Werewolves and vampires.
Deeper and Deeper
Some crazy dig dug or mining game… Again 😀 (i don’t want this theme.
Discovery
Exploration game.
Edge of the World
Exploration game with story 😀
Four Elements
Most boring theme of all times. You can make absolutelly everything with this.
Grow
Well… You can grow vegetables or… Human parts 😉
Harvest
Farming game (btw, there is no need to farm onions and potatos. What about monsters or humans?!)
Hidden World
There are many books about hidden worlds. Try check Jules Verne and Arthur C. Doyle (but i prefer Lovecraft 😀 )
Hunted/Hunter
Bunch of people in big house and randomly choosen murderer. Player can be huter or hunted too!
Indirect Control
This theme is best for artsy games. Like wind blowing on flyind dandelion seed. Or guy with noctambulism saved with ghost of his grandma/enviroment)
It Spreads
Nasty virus thing or Hippies from the perspective of army / police.
Self-Destruction
Check the news.
Take One, Leave the Rest
Sophie’s Choice or game about mysterious artefact but you can take just one in every level. Or Dizzy game with one inventory slot 😀
You are the Power Source
Game about robot in big spaceship. He needs to be fast and recharge systems. Something like super meat boy with little logic.
I hope this post helps 😀