Pixton is a character design site, comic creator, and more. With the site, you can create different avatar pics for yourself that you can insert into multimedia productions. It’s kind of like Bitmoji, but a lot more flexible. Your different classes can be grouped on the site, allowing students to create their own characters of themselves and use them in the comic book builder.
There is a Pixton add-on for Google Slides, letting you design and bring in characters directly to a Google Slides:
The free plan has enough to get started, and, after looking at the pricing of the other plans, if you’re going to use it at all it’s a pretty easy decision to pick the $99/year level ($8.33/month).