I love ChessPad 2. There are at least several others but I don't recall the names. This one is fast and pretty simple to install and use. Nice interface. I don't know if it's still supported, but IIRC it was updated in recent years.
One other is "Scid vs. PC". It's been ages since I used the original Scid (since I purchased ChessBase) but this successor to Scid has a great reputation. However I doubt it's as easy to use and comprehend as ChessPad 2.
Does anyone have any opinion on this matter...?
...come one come all, don't be shy...