rubber stamp
stencil
glue an actual business card to it and seal it
thumbprint and handwriting
decals or scrapbook stickers
gel medium transfers

Hand lettering with Pen and ink drawings that are each different

This will take a bit of time at the front end but once done it will be ready to make cards when ever you need to.
Its a branding tool and most accomplished wood craftsman have them for decoration purposes. Rework the tool and make the attachments (made with a heavy duty wire) into the shape of the letters or info you want on the card. when its done you plug it in and let it heat up and burn your info into the wood.

I have done it and like I said it takes some time on the front end but on the back "end" its great.

oooo fun! You can print nice stickers to go on them. You can even get clear stickers to take advantage of the pretty wood.

Make them useful by printing a calendar, sales tax chart, or tip chart on one side.
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I was given an interesting business "card" the other day - it was a scrap of leather with name and phone number simply stamped on it. The man made rocking horses and used leftover leather from the saddles.

Just get a stamp made up with your details and stamp with permanent ink