Obviously we prefer Session, SimpleX, & XMPP over Signal.  Signal still requires a number to register and is completely centralized to Amazon's AWS.  This being said, it's 1000 times better than SMS or WhatsApp groups.  So to celebrate Signal's new usernames feature to hide the number from group members, we now have a Signal Group:

https://signal.group/#CjQKICKP4m5jPiL-RdDH1Nx9ZapzJxd_YHwqsNVwGx-ABrezEhCuG2_aSzYcnl3mm5NBFO0x

(SimpleX/Session/XMPP Groups are still active)