The Royal School of Needlework has celebrated its 150th anniversary by making a Stitch Bank - a website where you can explore and learn different embroidery stitches. It's up to 200 now, with the latest addition of 50 newcomers in January.
You can find the Stitch Bank here. The stitch entries usually feature a series of photos and illustrations to show you how the stitch is done, plus a video. If you are all delighted with this and would like to support the project, there's the option of donating to adopt a stitch.
On a related note, here's an article about the meaning of traditional Ukrainian embroidery patterns.