A list of third party photo editing software

When newcomers to photography discuss whether to edit their photos on the computer and what to use, they ask various questions.

• Are there any free ones?
• Does the program have to be installed on the computer? (some people use work computers that don't allow installation
• Does it run on their Windows / Mac / Linux / Android tablet / iPhone or iPad?

I was thinking of what to say and then mentally crumpled that thought like a piece of paper. Made a grid so people can pick something. It's not comprehensive and may even be inaccurate.