What are requirements for 'best'?
If you want openings, then I would suggest any dB of long time control chess games played by masters.
If you want middle games, I would suggest any dB of long time control chess games played by masters.
If you want end game games, I would suggest any dB of long time control chess games played by masters.
Chesstempo works for me
I have wondered about these resources like the Games Explorer here at chess.com and other similar resources.
I just looked at the one at Chesstempo and realized it, like all the other ones, don't say if their games are long time controls or blitz/bullet.
It seems the most accurate ones would be long time controls.
For an aid in correspondence Chess, what is the best possible database out there? Preferably online...
Is Chess base best? Do they have an online version?
Also what would be the best free one.
How is the one here on Chess. Com compared to others?