John
Most responses have covered your options. Commercial branding irons in lots of different designs are available from Rockler and Woodcraft. My partners actually purchased a very nice one for me as part of my retirement gift. Probably other options on sites like Etsy.
Alternatively you can make (or have someone make) medallions out of wood or metal that get inlaid in your piece. With a laser cutter the design options are pretty endless. I have a Shaper and that can engrave similar to a CNC machine so designs are pretty flexible.
Hope this helps.
Jeff Greenberg
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