Dark does ×1 to Steel

Generations VI to IX, single types. The other way round, Steel against Dark, is ×1.

69 Dark and 65 Steel species among the 1025 this site covers.

Attacker, Dragon and Dark Roaring Moon sprite

damage×1Generations VI to IX

Defender, Rock and Steel Stakataka sprite

Dark against Steel has changed: ×½ in Generations II to V, then ×1 in Generations VI to IX.

Dark and Steel did not exist in Generation I, so Dark against Steel has no value there.

Strongest Dark attackers

Roaring Moon leads Dark at Atk 139

Sturdiest Steel defenders

Dual types that change the answer