Dwarves, with the exception of Dwarven Strike Force (and that famous Witch/Inquisitor, Soldier/Deserter, and Pirate/Ninja Mistform Ultimus) are generally small creatures, but their skill in weapon- and armorsmithing combined with their fierceness in battle makes them formidable opponents.
These two are the earliest examples of Dwarven smithing. Not exactly the most powerful mechanics in the world -- would you trade a card in hand or an artifact in play for a teensy size increase to a creature? -- but perfectly in-flavor.
Dwarves don't just enhance their compatriots with weaponry -- they also use tactics and inspiring war-speeches, as in Dwarven Lieutenant.
When it comes to skill with an axe, you gotta hand it to the Dwarves -- who'd want to get in this guy's way?
Here's a more recent example of Dwarven weaponsmithing, from Odyssey. Here, the pump effect is temporary, but then again, "A finely crafted blade will never meet as many blows on the battlefield as it did on the anvil." Again the effect is small, but you can activate Pardic Swordsmith multiple times for a 5/1 or 7/1 Dwarf.
Probably the most capable Dwarf ally you could have is Dwarven Bloodboiler. Part of a cycle of three-colored-mana-cost creatures with "tap an untapped X" abilities in the Odyssey block (see also Master Apothecary, Patron Wizard, Zombie Trailblazer and Seton, Krosan Protector), the Bloodboiler inspires fury in his allies with his battle cry.