If you are having trouble coming up with ideas for a fantasy game here are a few:

You could make a text based RPG

You could make a 8-bit side scrolling adventure game

You could make a first person RPG like the Elder Scrolls games (Morrowind, Oblivion, Skyrim)

You could make a top-down MMO RPG

You could make a procedurally generated dungeon crawling game

There are so many other types of games you could create aswell!