I don't care if it is something hard to make, I just want the outcome to be a fun and enjoyable game! So, Any suggestions?

a creative sandbox game, like MINECRAFT or GARRYS MOD

snookeems you are joking, right?

Garry's Mod would require knowledge on how to use the Raycasting Library, which it is difficult for me to learn, let alone, master. It is the same with Minecraft (Unless you mean a 2D version of Minecraft, then that would be easy to make) Also, here is another problem: (COPYRIGHT)