Sure, there are plenty of burn spells that actually burn; cards like Blazing Salvo, Flame Jet, and, of course, Fireball, are staples of red's approach to damage. But electricity, in the form of Shock, various forms of Lightning (Arc Lightning, Jagged Lightning, Barbed Lightning, Lightning Bolt, etc.) has always been around.
However, an often overlooked style of red direct damage involves using the earth itself to bring the pain. Cards such as Pinpoint Avalanche, Earthquake, and Rock Slide all let a red mage use the power of the land to attack their enemies. And that brings us to Skred:
The wizard on the left (just below the red glow from his staff) is causing an avalanche of snow to kill the giant on the right. In a way, he's using the mountains themselves to cause damage. And what could be more red than that?