Though each of our games have different Save File locations, their locations are generally based on their platform and the store they were bought from. Below are some general steps for finding your saves. Check out your game's FAQ for specific filepaths!
For Mac Steam games, a game's folder can be found under the file-path "~/Library/Application Support".
For Mac App Store games, the game's folder can be found under the file-path "~/Library/Containers". The game's folder should be named "com.aspyr", followed by the game's name and storefront, i.e. "com.aspyr.sims2.appstore". After opening that folder, navigate through Data > Library > Application Support > Aspyr, and you should encounter a second game folder with the game's files.
**Note that the Library folder your games are under is your User's Library folder, and is different from the one accessible to all users. It's also normally hidden. A quick way to view it is to open Finder, then select "Go" from the menu bar at the top of the screen. While in the drop-down menu, hold the Alt/Option key to display the Library folder, then select it.**
On Windows, most save games can be found by opening File Explorer and going to "%homepath%\AppData\LocalLow". From there you should be able to find a folder under the developer's name for your game, such as DigitalContinue for Next Up Hero or Bloober Team for Layers of Fear.
Most Linux save files can be found by going to "~/Home/.local/share/" in your file manager and then finding the name of your game's publisher or developer. Aspyr games will be in a folder called "aspyr-media".