The Year of Luigi Sound Selection was released in August of 2013 as a reward item for Club Nintendo Members of Japan. It was to celebrate the 30th anniversary of Luigi's appearance in the original Mario Bros. Other merchandise was available as well, such as a poster, coin, pin and 3DS XL case. The Sound Selection covers a wide array of games that Luigi either starred in or played a part in. A couple examples are Luigi's Mansion, Mario & Lugi: Dream Team, Super Paper Mario, Mario Kart Wii and Mario Power Tennis. I assume there was no fan input into the selection of this soundtrack(unlike Animal Crossing - Your Favourite Songs) but I can't say for sure because I can't find much information on it.
The price is getting up there for new copies of The Year of Luigi Sound Selection, the copies on ebay are going from $65 to $80. So, if you plan on picking up a physical copy, I would try and pick one up sooner rather than later. Our copy is uploaded in both MP3 and FLAC format and you'll find it in the archive.