- 雪が舞う季節Muq × Yutaka KasaiVocal1collabYutaka Kasai
- Glow In the darkのーぷ。(ちゃんこう) × Yutaka KasaiVocal1collabYutaka Kasai
- 銀結晶Acousticele7 × Yutaka KasaiVocal1collabYutaka Kasai
- evergreenHYDEVocal1collabYutaka Kasai
- Into OneAcousticele7 × Yutaka KasaiVocal1collabYutaka Kasai
- nearAcousticele7 × Yutaka KasaiVocal1collabYutaka Kasai
- LastRei × ちんかく × Yutaka KasaiVocal1collabYutaka Kasai
- 太陽じゃなくてもいい瀬野 或 × Yutaka KasaiVocal1collabYutaka Kasai
- The sun's embraceさばと × Yutaka KasaiVocal1collabYutaka Kasai
- 堕天hirame × Yutaka KasaiVocalYutaka Kasai