Some users would have private memes or streams where they organise their own. I haven't seen one that's public for all to use. But I think people would like it. I had an idea for doing something like that to make gifs more easily organised and available, but so far haven't got around to it.
If you do it, my suggestion would be to consider making it not just for upvote gifs but for other types of gifs people use as well: upvote gifs, thank you gifs, you're welcome gifs, and miscellaneous reaction gifs etc.
