Greeting cards, tags and other paper-mounted reproductions immediately come to mind and I know most of us have tried that. Very satisfying, and much appreciated by the recipient. My favorite is making custom wrapping paper. I found out that no one would actually use it, deeming it "too special." It's a not uncommon reaction.
What are the things people will use and enjoy? Here's a list, with a link to resources to create these items:
Coffee mugs: Select an artwork that can be reduced and still maintain some presence. Scan and size. Try this site:
Most print services require a minimum order, so figure out how many you want in advance. Leftovers make great gifts any time of year, or work well for point-of-purchase items during exhibitions.
Travel mugs are always welcome, whether for hot or cold drinks. Artwork can be fully reproduced as an insert in full color between an outer clear wall and the inner thermal wall. You can also stylize some of your artwork, so it works well in print, or create works just for this purpose. Try this site for inspiration and print services:
It takes a bit more money up front, but the resultant product is lovely and will be lovingly used. Scarves. Everyone is wearing them, and you can have a scarf designed with your artwork. These make great gifts, and great sales items for exhibitions. Try this site:
Another way to display your art in power circles is custom ties! Try the site listed below for more info and help thinking about design. They also make scarves:
And now, a one-stop, oh-so-many-ideas site - Walgreen's. Seriously. I was completely surprised by this resource, and the prices are...well... Walgreenian. Meaning, of course, very affordable. You are in Anything Can Happen Land. There are totes, and crystals (yep!) and mugs and water bottles. And scarves and ties and pajama bottoms and t-shirts and camisoles and performance shirts, whatever that means. A one-stop shopping opportunity, and the good part is, you can order just one item! That makes it possible to truly experiment, find what you want to do, and decide if more than one anything is a good thing. Check this out:
So, there you are. Food for thought, and possibly action.