Recently I stumbled across Stitching Cards, a site that sells downloadable e-patterns for embroidered greeting cards and bookmarks. Most patterns are a dollar or two, or you can raid the freebie section for some floral designs and an alphabet. I've seen 70s-style string art making a comeback on Pinterest— with these, you can try something similar on a small scale.
If you dig the idea of stitched cards but don't have the patience to do it yourself, check out Jeni Shirley's line of paper-and-thread creations. A source of inspiration!