Comics

https://readcomiconline.li/ has pretty much everything you'd probably need, just use ublock origin on firefox because it's ad hell.

The Kotatsu app on Android is mainly geared towards manga, but there's still a lot of non-Japanese comics.

Amber.

Interested as well

not a big comic book reader, but the few that I wanted, I was able to find them on https://getcomics.org

They are just jpgs compressed in .cbr (rar or zip) files, so I just unpack and treat them like jpgs.

I have downloaded a total of one (non-manga) comic from there, but MyAnonamouse (private tracker for ebooks and audiobooks) has a decent few and it's easy to join with just a quick interview--much less gatekeepy than most private trackers. Just read through the rules and requirements on the invite page and you'll be fine.

If you're on android you can download Mihon (https://mihon.app/) and then install the Keiyoushi extension/repo (https://keiyoushi.github.io/). It has a bunch of comic sources you can look for. It's been great for Manga on my e-reader, but I know there's a lot of comics available there, too.

If you're a homeserver nerd, you can set up a Komga service and then use an app like Tachiyomi for reading from your library. A bit involved if you've only got a few things, but the time investment really pays off if you've got a big library.