I have seen the NO BRAND back, but I have not been able to obtain one. I think the unbranded ones might be part of the Canadian set. I've seen them listed as C52, or Canadian T218. The backs say 50 designs, but they are also numbered, and I've seen numbers higher than 50, so I'm not at all sure on the checklist for this set.
I also have one from this T218 series with a Tolstoi back. I've only come across 2 with this back (and just noticed another sell on eBay recently), did get one of them and one I missed out on the other. I'm not sure where I can post this for you guys, but if you want, I can get it scanned. Is there a place that you just show different back types?
This set, having been released in THREE series, is quite difficult to describe. That's where some of the "variations" come in with different photos, having been released in a different series. I also believe one complete series, of the three, was only released with the Mecca back. I do have a checklist that I've put together from a few sources online that separates the set into the different series. Also, to get this really complete, I have seen some name spelling errors. I can post some of those when I come across them, if anyone is interested.