heroic heroes

[Taqwus]

Plenty of sources available. Check the Iliad and the Oddyssey for the heroes of the Trojan War, for instance -- most being known for leadership, morale, archery, armor, swordsmanship or perhaps the favor of the gods (think 'sacred'). Chariot-based heroes not unheard of either, hm.
Celtic/Arthurian -- sources that come to mind include Tolstoy's (no, not THAT one... a descendant) "The Coming of the King". There's also a collection "Celtic Myths and Legends" by a Peter Ellis, has a selection from Irish, Scots, Manx, Welsh, Cornish, Breton legends. Heroes would generally need to be toned down a bit for balance reasons -- e.g. I would not suggest including even the regular Fianna at face-value. The Ellis book has a long list of references at the back.