lucy24 - 6:20 am on Aug 26, 2013 (gmt 0)
The exact string "lr=213" only occurs in fake-referer requests. Most are already blocked by IP; I've retained the referer check just for insurance. I've never seen "lr=any-number-at-all" in a legitimate YandSearch visit; that's what makes it mystifying.
Far as I can tell, I've never seen 213.180 at all, ever, and didn't know the Yandex range existed :) Is this maybe a range Yandex used to crawl from, so "lr=213" is something you'd get in very, very old search results, now only preserved in fake referers?
There are several ranges on your list I've never seen in my life. Contrariwise I've got the 5.255 range noted above, and also 184.108.40.206/18. (220.127.116.11 YandexFavicon gets front page + favicon, 37.9.69-70 YandexImageResizer, UA list says it's for mobiles)