Verifier - Weed out disposable, non-existent domains or invalid emails.
Retweet Picker - Retweet Picker is an online tool that is helping you to select the random winner from Twitter for the giveaways.
Email Verification on Google Sheets - An add-on for email verification directly in Google Sheets
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.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
Twesocial - Twesocial helps you grow your twitter with real twitter followers. Real results, real people.