Pickerist - Instagram raffles from comments on 1-click
Retweet Picker - Retweet Picker is an online tool that is helping you to select the random winner from Twitter for the giveaways.
Tagwin - Instagram contests & giveaways made easy
Tweetdraw - Tweetdraw is an online tool that provides an easy way to pick a winner for a giveaway, having a quick Twitter Quote Draw, Instagram Comment Draw, and Twitter Retweet Draw.
Giv - Snapchat & Instagram giveaways made easy
Twesocial - Twesocial helps you grow your twitter with real twitter followers. Real results, real people.