Retweet Picker - Retweet Picker is an online tool that is helping you to select the random winner from Twitter for the giveaways.
Verifier - Weed out disposable, non-existent domains or invalid emails.
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.
Validator.pizza - Free API to block 🗑 disposable emails
Giv - Snapchat & Instagram giveaways made easy
Antideo - Email, IP address and phone number validation API service