Though in Final Fantasy you encounter dragons pretty early on, at least in VII you did, on the first disc and they're kind of a pushover. The chromatic dragons in the Gold Box D&D games are easier too, at least in Curse Of The Azure Bonds black dragons go down pretty fast. The hardest I've yet to face are in the roguelike Angband, the ancient dragons or 8-headed hydra, they breathe poison and can end up killing you in one turn.