ps. Wow... db25 kind is going for $500 new at Amazon! and this is just for the punch itself!
Yeah, the "real" ones meant for daily production use are rather pricey.
There must still be a source somewhere for chinesium-grade punch sets that are suitable for occasional use or hobby type applications. I recall seeing a set of all five D-sub sizes and the drawbar tool for about $150 in the back of some electronics magazine or maybe in Computer Shopper or something, many
many years ago. Seemed like a great deal, even if they weren't very robust.
I almost bought a set since in those days I used to fairly regularly have to cut extra port holes into the back of computers being built, upgraded or modified back then, but I never did get a set. Most of the chassis we were dealing with started coming with ample cutouts, even some with knockouts for the big SCSI connectors, although I wished I had a set many times later when building some other random projects, etc. as well.

They aren't that difficult to make (random dies and punches) strong enough for aluminum, plastic or very thin steel, I've made a few purpose-built ones over the years for various things, but if someone can find a source of some pre-made ones in some common modern styles, etc. it would be convenient.
I usually end up doing most of my panels on my old 1980s Dahlgren Wizzard XL computerized engraver. It's a bit of a pain to set up to cut panels and such compared to today's modern generic CNC router systems, but what do you expect for a 30+ years old system with TRS-80 internals for brains that was intended for doing things like making signs.

I'm just glad the thing still works!