Database without rapid and blitz games Last years Mega Database is full of rapid and blitz games taken from live broadcast boards. 

Is it possible to filter them out? 

Are there other bases that have games only from long time controls? 

I'd prefer to review long games only, so interesting novelty from your favorite player won't turn to be a game played in blitz game...
Here's a sample PGN header (player names are skipped to protect the innocent):

[WhiteElo "2027"]
[BlackElo "2370"]
[BlackIsComp "Yes"]
[TimeControl "180+0"]
[Date "1999.12.31"]
[Time "23:02:00"]
[WhiteClock "0:03:00.000"]
[BlackClock "0:03:00.000"]
[ECO "D00"]
[PlyCount "100"]
[Result "0-1"]


There's no consensus, which fields are supposed to be included, but as a safe bet, I'd recommend to look for "WhiteClock/BlackClock" as well as for "TimeControl" -- at least one of them is usually present, if not both at the same time.

"TimeControl" is basically easier to parse, but since it might be not included, you might want to process White/BlackClock as well, just to be safe.