In order of publication:
1. 文豪ストレイドッグス 太宰治の入社試験 - Dazai Osamu's Entrance Exam
2. 文豪ストレイドッグス 太宰治と黒の時代 - Dazai Osamu and the Dark Era
3. 文豪ストレイドッグス 探偵社設立秘話 - The Untold Story of the Founding of the Detective Agency
4. 文豪ストレイドッグス外伝 綾辻行人VS.京極夏彦 - Bungou Stray Dogs Gaiden: Ayatsuji Yukito vs Kyougoku Natsuhiko
5. 文豪ストレイドッグス 55Minutes - 55 Minutes
6. 文豪ストレイドッグス DEAD APPLE - Adaptation of the original anime movie, Bungou Stray Dogs: Dead Apple.
7. 文豪ストレイドッグス BEAST
Note: Dazai Osamu and the Dark Era was adapted into episodes 1-4 of the anime's 2nd season. Dazai and Chuuya 15-years old were adapted into episodes 1-3 of the anime's 3rd season