I'm looking for non commercial program where I can import PGNs. And to visualize the games I want simple GUI and analysis-table like you will find here. Additionally it would be nice if the program provides an interface where I can write my own statistics.
SCID does everything you are looking for, it's great chess database software.
Lichess has everything you need. It also updates a new list every month so the database always grows. Currently it has over 2,000,000,000 games. All in a pgn file. They also publish issues they have recorded to help people resolve their code. One more thing Lichess has is not only standard chess but also variants and puzzles all of which are separate and update monthly.