Discord          

discord.com

Slack          

slack.com

Microsoft Teams  

products.office.com

rocket.chat  

rocket.chat

Front    

frontapp.com

Spectrum  

spectrum.chat

SendHub  

sendhub.com

Stride

stride.com

Paltalk

paltalk.com

PoloniBox

polonibox.com

Relevnt      

relevnt.com

Ryver

ryver.com

Socialcast

socialcast.com

Sqwiggle

sqwiggle.com

Marco Polo

marcopolo.me

Talkomatic

talko.cc

Teamchat

teamchat.com

TeamSpeak

teamspeak.com

tlkio

tlk.io

Userplane defunct

Wavelength HCM      

akirawavelength.com

Wire

wire.com

Wishbox

wishbox.co

Yammer

yammer.com

Helpmonks

helpmonks.com

Campfire

campfirenow.com

Chatstack

chatstack.com

Echofin

echofin.co

Flowdock

flowdock.com

Gitter

gitter.im

Google Meet

apps.google.com

Gupshup

gupshup.io

Haiku for Teams

haikuforteams.com

HALL

hall.com

BlackBerry Hub

demos.blackberry.com

HipChat

hipchat.com

Hiver

hiverhq.com

IRCCloud

irccloud.com

Jive Software

jivesoftware.com

Kato

kato.im

Keybase

keybase.io

Kobra

kobra.io

LeanMail

leanmail.com

Mailburn defunct