How many categories for musicians to license songs?

Just the 4.

The pipe organ is a separate category and doesn't share with the piano like the keyboard does, so it does work.

If your musician is also into DJ mixing, they can license mix tapes once a week alongside piano, guitar, violin, pipe organ, and lyrics.

Yeah, they mix tapes from DJ mixing act like songs and lyrics: just one once a week. The music made from the Mix Master Music Station has a cooldown period, but it can be done daily. The royalties from the music uploaded don't end. I can't say it with 100% certainty, but that was from my personal experience with it. Eventually, the older songs only ever earned me 1-2 Simoleons daily.

yes I think just the 4.

"NightlyCoffee;c-18041061" wrote:
The pipe organ is a separate category and doesn't share with the piano like the keyboard does, so it does work.

If your musician is also into DJ mixing, they can license mix tapes once a week alongside piano, guitar, violin, pipe organ, and lyrics.

I just got a music mixing station for the household earlier today and haven't used it yet. I gather you are limited to just one licensed mix tape at a time as well?

I'm circling back to reply to my own thread because, now that my Sim has mastered and owns every available instrument I got the answer to the question i originally asked, and it is actually not the answer that anyone gave in this thread. I just want to make sure the info here is right, in case anyone searching for the same question gets this thread as a result.

Anyway, the answer is that there are 5 instrumental categories that can be licensed once per week, plus Singing allows lyrics to be licensed once per week, for a total of 6 licensed musical compositions per week (as of January 2022, with all packs owned).
Additionally, musical Sims who own the Mix Master Music Station and pursue the Media production skill can license a Mix track daily as well. Which is nice, seeing as the other 6 are all weekly, so it gives your Musical sims more to do.

I've updated the original post with this info.

I also thought it would be nice to list all of the different compositions a musical sim can write all in one place, seeing as all the guide sites I use have them scattered across multiple guides based on which skill they use. Hidden by spoiler tags because it's a long list: