I have chessbase 13 which I really enjoy (https://shop.chessbase.com/en/categories/chessbase) and I use the game collection that came with Fritz 13 with 1.5 million games.
As far as I know you usually have to pay for game collection databases, and there are subscription services you can buy to keep them updated. Chessbase has two offers -- their "big database" with over 6 million games, and their "mega database" for 3x the price, but I'm not sure what else you get.
There are many chess databases that you can interact with through a web broswer (chess.com and chesstempo.com are examples). But I would like to be able to download a nice multi-million master game collection of my own for some more in-depth analysis.
Any idea how to get ahold of such a collection, either paid or free?
Thanks!