There are over 600 keyboard shortcuts in Photoshop and I have tried to make them easy to find.
I have created a pdf that lists them all for both Mac and Windows systems.
If the pdf is opened in Preview on a Mac you can search to find the shortcut you are looking for.
I hope that there is an equivalent facility for Windows. On a Mac Adobe Reader does not seem to have a working search facility.
Noteworthy to see also that latest release of PS now recommends 16Gb or more memory. Last week I was able to run LR alongside PS (using the LR - Photo > Edit In PS route) with 8Gb memory but now find it crashes in PS then deletes both LR and PS instances. Additional memory on order !