Finding shortcuts is impossible without lots of searching (I wish adobe would make an app, or something for this!)
Anyhow, is there a shortcut to scale a clip to fit onto a timeline of different resolution? ie 1920x1080 onto a 1280x720 timeline I have to do this many, many times, so I'd like to see if there's a shortcut....
In the timeline it's done via right click>Scale to Frame.
But in Preferences, you can set the Default Scale to Frame Size option to make it automatic. (Only applies to footage not yet imported, though.)
Past setting in preferences, which you should do to your particular preference (mine is always Set-to!) you can go into the keyboard shortcut panel (Edit/Keyboard Shortcuts, Ctrl-Alt-K) and down to the Clip section, twirl down the Clip section, and you can set keyboard shorts for both Scale-to and Set-to.