One idea that i've been wanting to see implemented as a VRC+ feature for a long time, being able to upload your own custom emojis!
Imagine sending a pog emoji after winning a game of battle discs, or cheering on a performer with a custom heart emoji you uploaded! On top of being fun to meme around with, it could have genuine use cases.
There, of course, is safety to take into consideration. There should be an option in the safety settings to censor or mosaic custom emojis, like with user icons.
I'm so obsessed with this idea to the point that i've went and made a mockup of the image uploading process, and using them in-game.