The OD&D Elf
Elves are also called "Fairies" (Chainmail p. 29).
There are 2 sorts of Elves: Woodland Elves, and Meadowland Elves (M&T p. 16)
Elves may use magic armor and still act as magic-users (M&M p. 8).
Elves are able to speak the languages of Orcs, Hobgoblins, and Gnolls in addition to their own (Elvish) and the other usual tongues (M&M p. 8).
Elves have the ability of moving silently and are nearly invisible in their gray-green cloaks(M&T p. 16). When invisible Elves (and Fairies) cannot attack — or be attacked unless located by an enemy with the special ability to detect hidden or invisible troops — but they can become visible and attack during the same turn (Chainmail p. 28).
Elves armed with magical weapons will add one pip to dice rolled to determine damage. (M&T p. 16)
Elves on foot may split-move and fire (M&T p. 16).
Mounted Elves may not split-move and fire, for they are not naturally adapted to horseback (M&T p. 16).
Elves detect secret doors 1-4 in 6 (U&W p. 9).
Elves notice secret door 1-2 in 6, when passing by them (U&W p. 9).
Elves receive +1 in 6 chance to detect sound at doors (U&W p. 9)
Elves are about 3/4 the size of men (Chainmail p. 28).
Elves see in normal the darkness as if it were light (Chainmail p. 43).
Elves wielding a magical weapon add +2 to attack against goblins.
Elves wielding a magical weapon add +1 to attack against orcs.
Elves deal double damage against Ogres (Chainmail p. 28, ogre entry).
Elves move at 15" / 12" / 6" (deduced from Chainmail p.43)
Elves get no benefits from charging (deduced from Chainmail p.43 - no charge speed)
Elves are neutral but have a slight pre-disposition for LAW (Chainmail p. 34).
Elves wear beards (M&M p. 32).