My understanding is that they're sorted by categories - offering additional sorting options like alphabetical or maybe the option to mark a limited number of emotes as favorite doesnt sound like to bad of an idea though.

Until then: if you're using a keyboard you can type /x and hit tab - with x being the first (few) letter(s) of the emote you want. They're all in autotranslate and using tab allows you to pick the word you're looking for from a list of all possible words that start with that letter(s). So if you know with which letter your emote starts, you can use that (if you dont know that, sorting them alphabetically would make little sense).