Eh, did I mention they are 2mm? Whoops. Besides replacement leads from places like Amazon I haven't seen any. My original set fell apart and I ended up re-soldering them on thicker gauge with sugru insulation. Never bought others and definitely not in bulk.

Amrex sponge electrodes take banana plugs as do many carbon electrodes. In fact there's a recent link on here that has all of the above, if not quite in the Mouser quantities you might want.

I'll add it here.

They must be available elsewhere but I've just been using Amrex like these from Amazon for a while now.