Add your own in the comments and i will improve the list:
http://steemwhales.com/ – ranking of biggest STEEM stakeholders
http://steemstats.com/ – get stats on individuals accounts
http://www.coinmarketcap.com – see value of steem
http://coincap.io/ – alternative to coinmarketcap
http://www.steemimg.com – steem image hosting
http://www.openledger.info – decentralized exchange where you can trade STEEM for other cryptocoins
https://steemit.com/tags.html/trending – trending and best paying tags
https://steemd.com/distribution – number of members on STEEM
http://steemstream.com/ – watch STEEM in live action
http://steempress.io/ – convert steem account into wordpress like blog
Ned, "steem" CEO of Steemit, https://www.linkedin.com/in/nedscott
Dan, "Bytemaster", CTO of Steemit, founder of Bitshares, https://www.linkedin.com/in/daniel-larimer-0a367089
Application: https://steemit.com
Cryptocurrency & Blockchain Info: https://steem.io
Bitcointalk Steem announcement: https://bitcointalk.org/index.php?topic=1410943.220
Trending Posts: https://steemit.com/trending
Slack auto-inviter: http://steem.herokuapp.com