Automatically tiles windows for you as they are opened. Lots of options for how this is done, plus you can have different setups for different Spaces.
Another app that lets you move and resize windows, using keyboard shortcuts or snap areas. This one is based on Spectacle, which is no longer being maintained.
Organize your windows with easy-to-remember keyboard commands. Put them to the left, right, top or bottom. Put them corners. Centre them. Make them go full screen. It’s a great way to make comparisons, and it works in all apps. No longer actively maintained.
Easily organize your windows by dragging them to the edges of the screen, using keyboard shortcuts, or clicking on options in the menu bar.