D&D Companion: Weapons and Equipment

The D&D Basic and Expert Sets include sections on weapons and equipment, including armor.  The Expert rulebook also includes means of land and water transport, as well as catapults.

The D&D Companion Set (1984) describes several new weapons (bastard sword, blackjack, blowgun, bola, heavy crossbow, net, trident, and whip), as well as two new types of armor (scale and banded mail).

The D&D Master Set (1985) introduces the throwing hammer and four types of shield weapons, subdivides pole arms into halberds, pikes, and pole axes, and describes suit armor, several types of barding, and siege equipment.

Illustration by Erol Otus, from the World of Greyhawk folio (1980).

I would include the new weapons and armor described in the Companion and Master Sets as part of a Companion supplement, including siege weapons and equipment, (except for perhaps shield weapons).

Additional weapons described in the OD&D rules and Holmes Basic, but not in BECMI, include the morning star and flail.  These do more damage than a mace, although require greater space on either side to wield, thereby affecting marching order.

Additional bows described in OD&D and Holmes Basic, but not in BECMI, include the composite bow (same range as a heavy crossbow) and horse bow (a short, composite bow, same range as a light crossbow).

The OD&D rules also list helmets (separate from armor types), and belladonna (as a form of poison), in the equipment list.  Items from Judges Guild material include lodestones, etc.