Bookmark Manager, Linkwarden, ymarks, Google Bookmarks, Skloog, iCloud Bookmarks, Advanced Bookmark Search, Trove App, xBrowserSync, LinkCollector, Folkd, Turtl, Bookmark OS, Cloud Bookmarks and History, Bookmark Sidebar, Guardo, Highlights - Highlighter and Web Clipper, LinkAce, EverSync, Stash.ai, Nextcloud Bookmarks, TeamSync Bookmarks, RoboForm, GGather, DashMachine, Linkman, Rons WebLynx, LinkLocker, Transmute, BookMacster, LinqBox, Listango, Zapmarks, TabsFolders, Mixtags, launch.menu, bookmark buddy, Bkmks, Jumpon.io, Symgi, Opera Link, SyncPlaces, Startific, Eluma, Deng Google Bookmarks, Kloop, Mister Wong, Safavor, BookSmarts, Bookmarks Backuper, BkMarker, Pistashio, trackr.sh, ProjectMarks, Linkguardian, Bookmarks.io, favattic, Fav2Go, Arado Websearch are some alternatives to Firefox Sync.