Bookmark OS - Bookmark OS is like Mac or Windows optimized for bookmarks.
vdNote - Share noteworthy moments from YouTube videos.
BookmarkSheet - Your bookmarks in Google Sheets
Amie - GitHub for research and data science
Annotate.tv - Optimize your learning on YouTube
Grid Note - Grid Note is an app by Sumi Interactive that comes up with features to help you in adding notes in a grid layout to share your ideas and thoughts with the outside world.