Of the default patches so far I like Fantasia Horns and all the orchestra hits are nice and rich.

• Patch demos: https://www.synthmania.com/jv-880.htm

There are expansion cards available, but they're pricey. They also work with other Roland ROMplers (JV-, JD-, XP-, XV-) though not all are compatible across all machines.

• https://www.synthmania.com/sr-jv80-99.htm

More interestingly there's a DIY version so you can write your own data to it:

• https://www.sector101.co.uk/sr-jv-romulator.html
• Images of boards 1-19, 97-99 and a 1 custom: https://app.box.com/s/o5esgwsyp26fta61wrnm6hrgdhno7pad
• Images of boards 1-19, 97-99: https://comfybox.floofey.dog/resources/roland-sr-jv-expansion-board-dumps.251/
• Manuals for boards 1-17: https://drive.google.com/drive/folders/0BwbJMWoSOroQc3luMUJFbm5SVXM
• https://github.com/PythonBlue/SRJV - Python tools for getting the audio ready and onto the card.
• https://archive.org/details/20231014_20231014_1135 - JV80 Wave Extractor . . .