Greasy Fork is available in English.
Shows all pages at once in online view for these sites: Alandal, Batoto, BilibiliComics, ComiCastle, Comick, Dynasty-Scans, INKR, InManga, KLManga, Leitor, LHTranslation, Local Files, LynxScans, MangaBuddy, MangaDex, MangaFox, MangaHere, Mangago, MangaHosted, MangaHub, MangasIn, MangaKakalot, MangaNelo, MangaNato, MangaOni, MangaPark, Mangareader, MangaSee, Manga4life, MangaTigre, MangaToons, MangaTown, ManhuaScan, MangaGeko.com, MangaGeko.cc, NaniScans, NineManga, OlympusScans, PandaManga, RawD
Added, it was tricky one
Please consider adding http://read.egscans.com
It's the online reader of Easy Going Scans. They are not using FoOlSlide for their reader, so the script doesn't work on their website.
They are a pretty big scanlation group with more than 200 series.
I'd say that justifies adding them.