There have been a wide
variety of Russian, former Soviet and other 'combloc'
optic manufacturers over the years.
A very informative WW2-ish era list is HERE compiled by BADGER of milsurps.com
Some of the more notable factories
producing modern optics are:
The oldest is NPZ or NOVOSIBIRSK INSTRUMENT-MAKING
NPZ was founded in 1905 in Riga, Russia. From NPZ's website:
"Founded in 1905 in Riga where the first optical shops of German “Carl Zeiss” company were opened, the corporation combines its impressing traditions and constant development. This can be very well illustrated with the Herz panoramic scope, which was manufactured for the first time in the earliest years of the 20th century and is still produced by the plant."
Belorusskoe Optiko-Mechanichesckoye Obyedinenie (Belarus Optical & Mechanical Enterprise)
Since 1971 BelOMO has
produced a huge number of AK optics starting
originally with the POSP
series but in later years has dramatically
expanded it's designs to include very modern types
like PO 4x17, PK-A,
PK-AA, PK05 and numerous others.
BelOMO seems to have produced the widest variety
of magnified and non magnified optics and are easily
the most common 'combloc' optics found in the USA.
BelOMO tends to produce mainly POSP style optics and a
large number of red dot designs based around the older
PK-A series and the relatively modern PK01 series.