I’ve created a number of custom moods over time, but I have a few I would like to import into different soundsets from the one where they were originally housed. In the search bar, when I try to search for those soundsets, they don’t seem to pop-up- even if I select “my content” - is there some way I’m missing that allows me add them into a new soundset?
Custom moods built in the Fantasy Player are saved locally to your device and to the SoundSet they are built in. They can not be moved between SoundSets. Moods built in either the Web Player or the Online Player however are stored to our server and those can be duplicated to another SoundSet by using the Creation tools, which are accessible to SuperSyrin Subscribers.
This video talks all about moods and what you can do with them in the Creator; https://youtu.be/0oa4ktojy1Y?si=J6kLlbdTq6kPcVMJ
I thiiiiiiiiiiiiink you may be talking about moods you have made in the Web Player?
If so you can simply focus on the MOOD in its location in the SoundSet where you made it and select COPY from the MOOD inspector there and copy it to where you want it to go.
Do either of our answers answer your question? Who wins?!?!? 
This was the answer to my question- thank you so much! I was trying to search for them and add them to my soundset like you do with the pre-existing options, but mine never showed up.