So for the most part, any JVS adapter will work. What sort of video are you looking to use? If you're not planning on using the JAMMA connector for video (Naomi can output CGA or VGA from the built in VGA ports) it opens more options. I use a DB15 to JVS adapter and rewired my Vewlix cabinet to use a DB15 control panel (makes it easier to plug into different systems).
https://www.ebay.com/itm/284241920035
But if you're looking to use JAMMA, any of the adapters from Sega, Taito, Capcom etc will work well. You just need to be sure it supports the expected number of buttons for the games you're trying to run. Not sure which is the easiest to find these days...
Taking a quick look on the ebays...
Sega:
https://www.ebay.com/itm/354251624074
There are also some new designs out there:
https://www.ebay.com/itm/185354605049
Not had a chance to try one, but it looks interesting. Note that this is only JVS to JAMMA without video.
For power, I use a pico-atx adapter I put together to run a Naomi off a standard 12v power brick.
https://www.arcade-projects.com/threads/namco-2x6-jvs-pico-atx-power-supply-example.17014/
Shown above with an additional adapter to use with a Namco 2x6 system.