Lex Nova, a one off character from the 30 Days of Night comic, Bloodsucker Tales, fits this trope to a T. A completely batshit insane vampire who thinks he's a private eye and narrates his life out loud, Nova saves the town of Juarez from the various villains and only feeds on goats.
Julius Caesar as depicted in Asterix. He isn't above tricking people, but within far more defined limits than Asterix himself, generally being more clever than he is deceitful. He always keeps his promises, treats people below his station and even his enemies with respect (even when they're really annoying), and is one of the few Roman politicians we see who isn't plotting to backstab everyone else, stealing money from the state, being completely ineffectual, or fantasizing about getting the Gaulish magic potion and using it to kill their friends and become god-emperor. It should be noted that in no way is he a nice guy, though; he's still a colonialist tyrant who tries to have people executed, is delighted by various Villain of the Week characters with bizarre and horrible gifts, and is trying to destroy a culture's way of life simply because they're getting on his nerves.
Diabolik may be the King of Terror, but he will not harm children (and in fact he likes them), has little tolerance for human traffickers and drug smugglers and zero tolerance for rapists and biological weapons, tries to avoid collateral damage (not that he cares when he has to cause it), respects those who give him a run for his money, and will always keep his word.
Iznogoud: Sultan Pullmankar is mostly known as a ruthless conqueror and a terrifying enemy, but he has a lot of rules (including always sparing his enemy's generals), is very affable to the Caliph when they are allied, and is shown to be a pretty good father.
Moriarty: Moriarty is a crook and admits that he is not above killing people if they get in his way. But he's also genuinely noble and is willing to put his life on the line to help innocents.
In the series Saga, The Will is a Freelancer, a quite ruthless Bounty Hunter who will track his quarry to the ends of the universe and will kill even children without a moment's hesitation. But he has lines he will not cross, as demonstrated when he kills an alien pimp he meets on Sextillion after finding out that the slave girl he's offering to him is a six-year-old girl and later rescues and takes her in.
In Warlord of Mars, Joshua Clark differs from many previous villains, that while a ruthless man driven by revenge, he has a wicked sense of honor; he is willing to show mercy to Dejah if she tells him where her husband is, and not once tries to force himself on her. While he orders her execution when she attempts to escape and is unwilling to comply, he clearly laments being forced to do so. In the final duel between him an Carter, he declares that if Carter wins, then Clark's armada will abandon Barsoom's conquest and leave their world alone.
Princess Lucinda from the reboot of Witch Girls Tales, so much. She has quite a sadistic side and a reputation as an evil princess... but for all her loudly proclaimed villainy, she almost always seems to end up on the side of good, despite her rather Nightmare Fuel-riffic methods — even by the standards of the setting, which is loaded with Body Horror transformations and remarkably casual murder. It's actually lampshaded in one side comic, where it's noticed that unicorns will approach her, despite supposedly being amazing judges of character that never approach anyone evil. When someone suggests that this means she's just acting evil, she turns them into a frog for it.
