Light Yagami and Bill Cipher.

Why?

Well, maybe it's just me. Light is widely known as an anti-hero/anti-villain, rather than pure evil. And Bill - well, given his charisma and popularity, you don't need to personally check the number of fanfics where he gets a pair of leather pants. Besides, since the book came out, I mostly hear that people feel sorry for Bill. And to be honest, me too.

I would say General Grievoud since there are so many people here who say he shouldn't be PE.

I think there is only one person who says General Grievous shouldn't be Pure Evil but they are making multiple accounts.

Syndrome: They think that he’s tragic since Mr. Incredible’s rejection towards him was uncalled for. Even if he felt bad for being harsh, Buddy still put himself in danger of being killed by Bomb Voyage because he wanted to fanboy over Mr. Incredible and he only wanted to be a hero for selfish reasons. He’s the embodiment of toxic fans who do anything to please their idols and then try to destroy their lives when they feel they don’t get what they deserve.

Scar: They think he was bullied by Mufasa when his crimes were driven by envy and thirst for power, and say the venom corrupted him into becoming evil when in truth it only amplified the evil that was already in him (plus Kion was also affected by the venom and still had some control).

Lotso: People think he’s tragic because Daisy abandoned him and hoped that he would redeem himself, but Daisy didn’t know he was alive and he forced Chuckles and Big Baby to share his suffering, eventually passing it on to all the toys under his tyrannical rule of the daycare.

King Magnifico: “He made his kingdom prosper and he doesn’t get any appreciation for it.” “He has every right to rescind wishes from people who want to make wishes for evil purposes.” “He’s an extremist and Asha is the real villain.” “He didn’t deserve to be sent into a fate worse than death because of all the points above.” He was intended to be a homage to classic Disney villains with no redeeming qualities, but the writing of Wish made him more redeemable than the actual redeemable villains.