• High School DxD/ Star Wars
• High School DxD/ Marvel
• High School DxD/ DC
• High School DxD/ Worm
• High School DxD/ RWBY
• The Rising of the Shield Hero / High School DxD
• The Rising of the Shield Hero / Worm 
• My Hero Academia / Worm
• Percy Jackson/ Star Wars
• Percy Jackson/ DC
• Percy Jackson/ Worm [I keep on imagining Percy vs Leviathan]
• The Wheel of Time / Percy Jackson
• The Wheel of Time/ Worm
• The Wheel of Time/ Harry Potter
• Ben 10/ High School DxD
• Ben 10/ Star Wars

Canon isn’t necessary. For instance, in a Ben10/ High school DxD story, you do not have to bring in Ben & Gwen. A random character (OC or not) can gain the Omnitrix (perhaps as a sacred gear).

Are some of these crossovers weird? Yes. That's the goal lmfao