My two favorite types of embroidery are blackwork and chainstitch. One of the best embroidery references I've ever seen is: The Stitches of Creative Embroidery by Jacqueline Enthoven. I generally have a basket cloth I'm currently working on in my purse to pull out while waiting on appointments and such.
Once you've developed a skill for reading graphs, it expands your resources immensely. Needlepoint designs can be used for beadwork, bead patterns for filet crochet, anything which is graphed can be turned to a variety of arts.