Thanks to: sideproject
http://news.ycombinator.com – (duh), post with Show HN, easy submission, will get listed on http://showinghn.com/ and http://hnshowcase.com as well.
http://betali.st – quite well known, moderated, gets a decent amount of traffic if you get featured, not too many form fields to fill out.
http://www.kickoffboost.com – moderated, and relatively new, easy submission
http://www.reddit.com/r/sideproject – moderated, easy submission
https://www.sideprojectors.com – relatively new, easy submission
http://thestartuppitch.com – moderated, has quite a few more form fields to fill out than others
http://www.erlibird.com/startups – paid $149, last time checked out
http://forrst.com – Easy submission, used to be a great community for feedback – not sure now
http://www.bootstrappist.com – a mailing list of bootstrapped projects – has quite a few subscribers I think.
http://angel.co – Angelist, of course – new startups gets tweeted via various accounts
http://crunchbase.com – Crunchbase – similar to Angelist