A covey of judges

A panel won't work as it's a rather specific collection of judges (to decide an appeal). Wikipedia has a good definition: https://en.m.wikipedia.org/wiki/Judicial_panel

In all honesty, I can't recall a term, if there even is one.

Judges are human beings. I would use the same collective for judges that I use for any other humans.

A group of judges is fine, or a gang of roving judges.

Bench.

Thank you!