We are currently preparing patch 2.9 for release, and we are focusing on clearing some of the searching features that we have received (thanks for all the feedback!). One of the bigger features that we have been working on is allowing you to search for cards by the color of mana it produces -- great for quickly finding the lands that you will need to finish up your buy list or deck.
You can only see on the picture the inclusion of Only for card color searches -- so searching for "Red and Green Only" will exclude all cards that are of any other colors (i.e. red and blue cards etc).
A picture tells a thousand words -- so check it out below!