InviteRobot - Instant subscription for paid Slack communities
Whisper.sh - Whisper is the best place to express yourself online. Connect with likeminded individuals and discover the unseen world around you.
SlackPass - Subscription access to anything with Slack
Sayat - Sayat app is all about getting anonymous and honest feedback.
Grapevine Surveys - Grapevine is an online survey tool for employee surveys.
Sarahah - Sarahah is a Social Networking Application for providing anonymous feedback launched in 2016 and available to use on iOS and Android platforms.