Facebook Groups - This app gives you a dedicated space for you and your groups
MemberPrism - open source alternative to memberstack / memberspace , but with both front and backend member-only content protection - easychen/MemberPrism2
Mobilize - Mobilize is a scalable messaging app built for large groups.
Fanfix - Exclusive, behind the scenes content from creators
Telegram Desktop - Fast and secure desktop messaging app, now updated
Crowdstack Pro - Engage, retain, and grow your community