For a prominent example in the dub, listen to Kaiba in the first episode of the edited version. Then listen to him in the uncut dub — he's a lot louder and sounds more like Brock from Pokémon (which is little surprise, as they're both voiced by Eric Stuart).
Japanese dub Kaiba also screams almost everything he says when he's dueling.
In the Singapore dub of the series, most of the characters (especially Yami) simply yell out all their lines. Even so, it is often preferred to the 4Kids version due to the script's closer translation of the original.
The Japanese dub has Yami Yugi when he's dueling. He's really loud, even when performing unspectacular turns.
The worst offender might be Espa Roba, who seems to scream every single line. Lampshaded in the abridged series with Joey saying "Stop yellin' at me!" to which Espa Roba replies "WHAT? THIS IS MY NORMAL SPEAKING VOICE!"
Kabuto Kouji from Mazinger Z in particular doesn't seem to know when he should be done screaming. More seen in battle though, considering that Kouji is pretty normal when talking casually. Boss on the other hand...
Tetsuya Tsurugi from Great Mazinger is better on this respect, and then, the latter part of the series happened and Tetsuya suddenly does this nearly ALL the time. On the other hand, Duke Fleed from UFO Robo Grendizer is pretty calmed WHEN he is out of his Humongous Mecha. When he is piloting Grendizer, though...
In the anime, Byron, the Canalave City Gym Leader. Dan Green seems to be trying to make him the Pokémon world's answer to BRIAN BLESSED.
Jessie in the 4Kids dub of the anime. Also when competing in contests as "Jessilina".
Black of Pokémon Special is also an example, as when he's not training or helping White, he's standing around yelling he's going to win the Pokémon League.
Although the Digimon dub is generally a lot louder than the original, Doug Erholtz (T.K.) gets the cake. It doesn't matter how the scene is or what kind of voice tone it requires, it always seems the actor is yelling into the mic at the studio.
And how could we forget the Largest Ham in Digimon history, Etemon.