Where to find it:
Petrov Defence - Games in PGN - 10,000 Games.
Base

Database
The Grob Attack in CBV. 8000 games?

Herbie Eröffnungstheorie: Die Owen-Verteidigung 1.e4 b6
Eröffnungstheorie: Die Owen-Verteidigung 1.e4 b6
Downloads at bottom of page.

e4e6.com - Home
The page is in Italian. But where are the games?

Antiques, Perle Antiche, Dossier
Downloads in many formats.

Chess Tournament and Match History
A history page of great players with games added.

Chess Games Links maintained by Lars Balzer - Links to chessgames around the internet which you can download for free

Annotated chess games collections of famous players
Games in Fritz, CBV.

Many Openings:
[Chess File Downloads -- PGN: Openings] >> Chessopolis! <<

Chess Openings Database | Free PGN Chess Games | ECO C03 French, Tarrasch
2.6 million games.

The Center Game:
Chess openings: Center Game (C21)
Note - Free total downloads for members.
Chess Games contains Openings by ECO number, and played by GMS.
C21 is one sample.

Free Software Windows and Mac for Opening study.
Includes Fritz, and SigmaChess (Mac program).
Chess Openings Links

Encyclopedia of Chess Openings
ECO for downloads.