I'm so glad this was asked, we were too scared to ask and were also wondering the same thing
What is transplural? SRRY if this seems dumb but chrome isn't helping ðŸ˜
Totally fair! It's a niche tumblr thing;
It's people who aren't systems/plural (DID, OSDD); who want/pretend to be, they're basically romanticizing or faking a mental illness; and are using the 'trans' label to justify it. I don't know why these people specifically chose plurality, but they did.
(Before anyone gets mad at me, I am a system myself)