Note types with + after their names usually appear when you import shared decks: Note types with strange names - Frequently Asked Questions
You can safely remove unused types.
Anki adds the notetype named “Image Occlusion” automatically. If you remove it, it’ll be re-created when you open the Add screen.
I think @glutanimate plans to work on adding a way to convert IO Enhanced notes to new built-in type. The built-in type has less features currently. I recommend using it for new notes if it serves your purpose.