YouTube Decade - Watch the most viewed videos posted exactly 10 years ago
Vidooly - Get deeper analytics of any YouTube channel or video
CDNPerf - CDN performance and uptime statistics
SimilarChannels - Find similar YouTube channels, discover new channels based on your interests, create your own YouTube collections with your favorite channels.
mlytics - Boost websites and apps faster and safer
YouTube Trending - Making it easier to find viral videos