Fairy does ×1 to Grass

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

64 Fairy and 127 Grass species among the 1025 this site covers.

Attacker, Psychic and Fairy Hatterene sprite

damage×1Generations VI to IX

Defender, Grass Leafeon sprite

Leafeon #0470

Fairy did not exist in Generation I and Generations II to V, so Fairy against Grass has no value there.

Strongest Fairy attackers

Hatterene leads Fairy at Sp. Atk 136

Sturdiest Grass defenders

Dual types that change the answer