Hey there!
At the moment there is no way to check only for specific rarities of items in the AH, chosing from the "Rarity" dropdown only allows to exclude items with rarity below the chosen one, but not above, so it would be helpful if there were the option to mark a second rarity to also exclude rarities obove the chosen one(s).
A situation where this would come in very handy is while filtering for monster cards. Right now there are almost 1,5k red-rarity cards in AH, leaving only 500 entries for all other rarities, making especially many blue-rarity cards impossible to find, since the AH finds results starting at the highest rarities. So being able to exclude red-rarity cards for example would be very helpful here and I bet there are many other situations where players would have use for such an option.
Thanks for taking this into consideration!
Cheers