I love punched metal art. I used to have a super metal company and could buy good, commercial quality ones for examples and such. We're talking like five bucks for a wheat pattern critter 16" tall. So I bought a few, for inspiration.
I did a few, just tin punches because I can. I used flashing from the big boxes.
I bought a set of Harbor Freight cold punches and re-ground them for different effects.
This is a little like glass etch. You'll start looking through magazines and thinking in terms of silhouettes for patterns. Also, don't overlook leather work patterns.
Oh, and you're off to a GREAT start. Keep on keeping on.