In Sword, Shield, Scarlet, and Violet, there are no Mossy Rocks. Instead, Eevee does indeed evolve into Leafeon via Leaf Stone. There are Mossy Rocks in Brilliant Diamond, Shining Pearl, and Legends: Arceus, and using those or a Leaf Stone will suffice.
Generations prior to Sword and Shield obviously do not allow Eevee to evolve via Leaf Stone, as Mossy Rocks do exist in earlier games.