Replacements?

Lmao, I've heard about riot here and literally one day after i got it their own servers were hacked
good one

Signal for privacy and security.
Telegram for big group of people/friends with "okay" security.
Or if you're a real PR0 H4RDC0R3 G4M3R that just wants something besides Discord, look into the Overtone App. Pretty much same design but won't sell your data to third parties.

E-mail.