Ore no Imouto ga Konnani Kawaii Wake ga Nai., Kuro to Kin no Akanai Kagi. Recommendations
Both anime are about the love story of a brother and sister relationship.
The difference between the two:
Oreimo 2 is a Harem while Kuro to Kin no Hirakanai Kagi is a Reverse Harem.