I really like the dragons in Skyrim. They're a nice simple design and have a number of varieties
I never really liked how they don't have forelegs, just weird little grabby hand appendages on their wings.
I'm going to second Gregori from Dragon's Dogma.
The dragons of Guild Wars 2 are plenty evil. They're all apocalyptic world eaters who decimate entire kingdoms and corrupt their populace.
In the base game Zhaitan presides over the ruins of the kingdom of Orr, which it raised from the depths of the ocean. His power turns any creature slain by his undead into another one of his grotesque minions, adding another mindless servant to his hoard. I'm used to the whole turn into a zombie thing, but somehow GW2 makes it horrific and tragic.
Mordremoth from the expansion Heart of Thorns is similar, corrupting his victims into mindless grotesque plant monsters. Mordremoth commands an entire living jungle. In Heart of Thorns the jungle is alive and can kill you! At the outset, Mordremoth commands the jungle to tear an entire airship fleet out of the sky. At night, the jungle literally comes alive and attacks players, instigating an event period where players have to team up to survive until sunrise.
Kralkkatorrik also corrupts the creatures he slays, but he turns them into crystal monsters. Kralk's crystal fire breath burned a massive crystal wasteland over an entire region called the Brand. It's miles wide, covered in jagged crystal and teaming with the hoards of crystallized minions who were caught in its breath.
Dragons in fiction have been presented as woosies for far too long. In Guild Wars the dragons are just as dragons should be. Ancient, unfathomably huge, a destructive force commanding dominance over entire lands. They keep to themselves only because they desire to, but their ever present threat is everywhere even when they aren't seen. They're literal heralds of the end times, since it is revealed that they are eating the world's magic and will bring about its destruction if not stopped. They are eldritch, pitiless, and regard everything else as nothing more than useful disposable tools to them. They're the ultimate evil.