Edward "Whitebeard" Newgate (One Piece); when Akainu killed Ace
Saitama (One-Punch Man)
Kenshin Himura (Rurouni Kenshin)
Meliodas (The Seven Deadly Sins)
Shachi Kamishiro (Tokyo Ghoul)
Pharoah Atem/Yami Yugi (Yu-Gi-Oh!)
Kurama (Yu Yu Hakusho)
Asura (Asura's Wrath)
Doomguy (Doom series)
Sephiroth (Final Fantasy VII)
Kratos (God of War)
Ryu Hayabusa (Ninja Gaiden)
Jake Muller (Resident Evil)
Albert Wesker (Resident Evil)
Even with his easy-going attitude, Son Goku (Dragon Ball Z) felt rage at the loss of his friends when he faced Nappa...
...and even with his heart tainted of seeing his best friend, Krillin, die before his eyes, it was a quiet but fierce battle against Frieza.
Meliodas (Nanatsu no Taizai) is called the Dragon Sin of Wrath due to his dangerous and destructive temper. After training in Istar, he has not only regained his full power but achieved a state of quiet and controlled fury through projecting it at a constant rate in battle.
Even in their younger years, as part of the Hyuga Clan (Naruto) Neji and Hinata fight with controlled tempers and careful precision.
Uchiha Clan members such as Madara (Naruto), were notoriously gifted fighters. Taking on multiple opponents without a shred of emotion.
Though usually carefree, Monkey D. Luffy (One Piece) can still be silently yet extremely enraged.
Despite Doflamingo's (One Piece) relaxed attitude, he does have a temper, shooting Law three times, his plans for SMILE ruined, being dethrone, Luffy's interference and desperation to kill him, he still retains his trademark smile because he couldn't get any madder.
Kurama's (Yu Yu Hakusho) anger made him act on the impulse to kill Gourmet and sentencing Toguro into a lifetime of suffering.
Rupert Giles (Buffy the Vampire Slayer) was consumed with rage after Angelus killed Jenny Calendar, burning down his lair and beating him with a flaming baseball bat while remaining calm and collected.
By his own admission, Bruce Banner (Marvel Cinematic Universe) is "always angry", allowing him to freely shift into the Hulk.
By using the pain of losing his wife, the loss of his limbs and his new agonizing cybernetics, Darth Vader (Star Wars) was of the most powerful Dark side users in universe.