I need these and this is a good place to put them. Any playwright that fits the qualifications for the play submission can submit to these, so I figure that I'll leave this open so people can find it, too.
Leah Ryan's Fund for Emerging Writers
http://www.leahryansfeww.com/apply.html 10 by 10 in the Triangle
http://artscenterlive.org/artscenter-stage/10-by-10/ Carnival of Flowers
http://www.toowoombarepertorytheatre.com.au/html/2016_one-act_playwriting_competition.html MN Shorts (though I see nothing about submission)
http://www.mnshorts.com/ The Robert J. Pickering Award for Playwriting Excellence
http://www.branchcct.org/pickering The Mountain Playhouse International Comedy Playwriting Contest
http://www.mountainplayhouse.com/index.php/about/playwriting-contest