Alphabetically:

Ajack
B&L
BSA
Bushnell
Cabela's
Herter's
Kollmorgan
L.M. Dickson
Leupold
Litschert
Lyman
Maxwell Smith
Nikon
Norman Ford
Pentex
Redfield (Denver)
Redfield (Reborn)
Savage-Suwa
Sightron
Simmons
Stith (Kollmorgan)
Stith (Weaver)
Tasco
Unertl
Universal
Weaver (El Paso)
Weaver (Reborn)
Zeiss

A couple of European sniper scopes, British, Swiss, and Swedish, that I'm not sure about their actual manufacturer.