I made these about 15 years ago now I'd say, and then had them printed out like proper cards. Just wanted to spice up the development card deck a bit as the three standards don't exactly set the world on fire after a while and we really loved Catan back then. Some of these are probably a bit broken, but hey it was just a bit of fun.
Of course, to make things match I had to print out the knights and all that too (and cut all the corners out by hand!), but also because I naively intended to include all the new cards at first (a couple of each like the originals) I had to proportionally bump up the number of the other cards to avoid wrecking the balance! A lot more work than expected...
Anyway, I just thought it might be nice to share. You'll probably recognise some of the artwork that I pinched!