Thought I'd make a special note that ulx playsound now autocompletes. It's only pulling in information from the client, so you may try to go play a sound and find the server doesn't have it. Also, anything without an extension is a directory, and you'll need to insert a slash '/' to see into it.
I tried playing around to make the directory slash auto-insert, but then there's no way to autocomplete the contents of that directory.
What do you think? Is there any way to improve this?