vdNote - Share noteworthy moments from YouTube videos.
hashtags.org - Hashtag is an extensive hashtag research platform for analytics and tracking of hashtags, providing...
Hubub - Host better conversations around video.
HashtagWiki.com - Hashtag Generator Tool
Bookmark It - Create awesome notes on YouTube videos
RiteBoost - Auto-hashtags, Auto-emojis, GIFs and much, much more, all according to your Enahce rules.