Misskey and its forks have this feature, with support for custom instance emojis as well.
Think of it like you can react to a message from another discord server with an emoji you made on your server. Pretty cool!
JP
@jeanpaul.eurosky.social
51 followers 101 following 7 posts
Used to be into software engineering but watch me pivot into geology in the future ;) Not a big poster, but maybe someday I will be!