Comic Club have collected online comic resources together so you have a  range to choose from on a single page. They include some comics for reading, and some ideas for making your own.

https:// comicsclub.blog/online-resources-2/

(NB: I’ve added a space into the link above so you can see the address)

This is another list of online comics, some suitable for primary and some for secondary pupils.

https://www.slj.com/?detailStory=webcomics-teens-tweens-free-middle-grade-YA