I just gave this a quick run. There aren't many options; however, it's very easy and quick to use. It can definitely suffice many use cases.
Doodle - Make meetings happen. With Doodle, scheduling becomes quick and easy.
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
WhenIsGood - Plan the time to have your meeting or event by co-ordinating availability with all the particpants using this fuss-free online tool.
Bookmark OS - Bookmark OS is like Mac or Windows optimized for bookmarks.
Framadate - Make your polls
Freezetab - A powerful alternative to bookmarks.