https://www.trailerpartsdepot.com/p-...ted-81251.aspx
These are the OEM ones that fit those calipers. I just went thru the same thing myself and have the same calipers as @
802spinnerbait on my Z7 trailer. You can also sub in pads from a 1990 chevy caviler but those wont be stainless backing plates like these and will be prone to rusting themselves to the caliper.
One other thing, when you put it back together the owners manual for the brakes says to use "permanent" AKA Red lock-tite on the slide pin threads. They suggest putting it on the holes in the backing plate prior to mounting the caliper.