Palestrina stitch is one of my all-time favorite embroidery stitches. It creates an interesting line with texture to it, thanks to the knots...Instructions @ http://www.needlenthread.com/2013/04/stitch-fun-palestrina-stitch-edge.html
Lovely Stitch Sampler
Stitchery Tape. This is what makes your finished cross stitch and embroidery work lie perfectly flat forever. Super easy to use and archival, so it will never yellow.
Bargello magic (not sure if I could actually make this, but one can wish!)