Wow, nice webpconverter plugin! I'm feeling very stupid right now. I made something like that for myself before but it converted the images to webp when uploaded in kcfinder. But it used this as a library installed via composer. I really didn't know imagewebp() was a thing 😕 .
I'm for sure gonna use this 😃
OT: My most used plugins are Formlister, MultiTv, PageBuilder, Doclister (DLmenu and such), YAMS, IF and sometimes ajaxsearch. I modified PageBuilder to have different tabs in each block for multilanguage sites, i could share it if someone is interested.