AHHH I fucking hate microsoft :D
You forgot Azure DevOps, their attempt at a JIRA/project management ersatz.
Also Skype, that is sometimes called Lynx, or Skype for Business.
Lync* actually, so imagine talking about new things coming to the System.Linq namespace and the migration to Lync from MSN Messenger at a .NET shop in the late 2000s, confusing the heck out of everyone.
Afaicr, Skype for Business (aka Lync) is a completely different codebase / program than Skype.
They rebranded it when they bought Skype because everyone hated Lync so much.
Which... to be fair, Lync is the only application I've known that's dumb enough to repeat failed login attempts with the same incorrect credential until the account is locked.
Found out when I'd rotate my AD password and a box I was remoted into would promptly lock my account by trying to use the old cached auth.
With you 100%, nobody's worse at naming things than Microsoft. I'd say the only real contender for its throne is Google with its Messages/Allo/Duo/Hangouts Chat/Hangouts Meet/Google Chat.