Black Friday is coming and the offers at Modern Chess are even better now: 

Partner Products 70% Off 
Camp Databases 60% Off 
Opening Databases 50% Off 
Middlegame Databases 50% Off 
Endgame Databases 50% Off 
Learn from the Classics 50% Off 

Modern Chess' own databases have a very informative preview, 
you get reasonable pgn-files and to most of the newer databases some videos too. 

You should really take some time to read the previews, 
otherwise you could easily miss something interesting. 

Just one example: 
GM Papaioannou did a camp database about the 
Bogo-Indian. This includes as a bonus a universal system against 
the Catalan, the Nimzo-Indian and the Bogo-Indian. 
This system is not optimal in the Nimzo, but a good starting point to reach playable positions without learning much theory. 
Later you can upgrade with more theoretical stuff step by step.

60% off on all 1d4 databases.

They are on a great variety of lines at a reduced price. So you might want to check it out and see if there is anything you want to pick up.