I very much enjoy buying glasses with etches that I do not recognize. For one thing they are usually less expensive than well known patterns. So I have bought a number of glass identification books to help me. This set of guides are probably my favourites. I bought one somewhere, liked it so much that I ordered the other three. I like having the colour photos. I find it much easier to identify patterns from colour photos than sketches, or even worse, black & white photos.
These guides offer a variety of etches, cuts, blanks from different companies and eras. I highly recommend them.