European OT character set – W1G
At the moment there are four distinct categories of OpenType fonts: OpenType Std, OpenType Pro, OpenType Com, and OpenType W1G.
All OpenType W1G Fonts at Linotype.com
Fonts in the OpenType W1G category contain a defined minimum character set. This includes Greek (Monotonic) and Cyrillic. W1G stands for “World Glyph Set One.”
Characters for OpenType Pro (gray) and OpenType W1G (gray + black):

The gray letters in the image above display glyphs from the latest Pro character set. The Black glyphs are additions found in the W1G character set.
In addition to the characters listed in the “Pro” version, OpenType W1G fonts contain characters for the following 23 languages:
Agul
Avar
Balkar
Belarusian
Bulgarian
Chechen
Erzya
Gagauz
Greek (Monotonic)
Ingush
Karachay
Khvarshi
Komi
Komi-Permyak
Lezgian
Macedonian
Moldavian
Nenets Tundra
Ossetian
Russian
Rutul
Serbian
Ukrainian
Some of the fonts in the OpenType W1G category may contain additional glyphs or other typographical character variants.