I'm sure you have seen this trend for awhile now. I was inspired initially by the Viceroy hotel lounge and thus began my fascination with doing this in my own home...
Viceroy Hotel Santa Monica
Pottery Barn (I think)
But as you can see the plates usually have some sort of theme, at least the ones that look the best have some thread of consistency going through them. I went with graphic plates, that all have black in them and then I added a variation, I added letters(an ampersand and a woodblock A, which is a little hard to see). So in the end it is mostly plates with a few oddballs here and there but I do love it and how it looks on the archway of my kitchen. I do need to add a few tiny plates or letters to complete it but those aren't something that you can find as easily as full size plates.
My two favorite plates do come from ebay and they were purchased from a vendor in Sweden and Germany. They are the Scandinavian plates, one is pretty old the other, black and white one is newer but it has the same style as the older one. I need to troll ebay again for some more plates in smaller sizes, hopefully I can score some more for cheap. The scribble line plates are from Crate and Barrel from some time ago and the line drawings are from Spain, they came in box set that was with cups and bowls - supposed to be Picasso, not sure if any of the drawings were done by him and they were reinterpreted onto plates or they did it in the Picasso style - which they do look like.
I know the colorful plate doesn't really go with the rest of them but I really like it. I picked it up in the Philippines with my husband and its hand painted on wood and technically it fits because it does have strong black outlines on the plates. Either way it's staying until I find something to replace it or add something to make it fit.
I have no clue why my wall looks like its a different color in each pic, its actually a neutral khaki, this last photo is really green looking, maybe it was the waning light of the day.
Yeah it's still a work in progress...