Petapixel is a useful site...has good articles, reviews and tutorials, as well as an equipment section.

This article is a repository of links to software organized by:

• Photo enhancers (1-3)
• Online editors (4-21)
• Free desktop editors (22-26)
• Paid desktop editors (27-40)
• HDR photo editors (41-53)
• Cross-platform image editors (54-57)
• Photo filters (58-66)
• Photo editing mobile apps (67-85)
• RAW processors (86-96)
• Photo viewers and managers (97-99)
• Other (100-104)

There are MacOS and Windows apps, as well as prices...honestly, it's a valuable resource. 

With regard to the online editors, one thing I'd advise is to look at the TOU...because you don't want anyone laying claim to nor using family, etc. images, nor selling them to companies as stock images for profit.

Anyhow, for folks who are beginning in image editing and who don't wish to spend money just yet, this might be useful...also for folks who wish to touch up older/faded images, etc.

Hope this helps...

Link:

http://petapixel.com/2016/08/30/104-photo-editing-tools-know/