It's called CUA.
https://en.wikipedia.org/wiki/IBM_Common_User_Access
There are dozens of them out there.
Random example:
https://www.system-overload.org/windows-shortcuts.html
General guide...
Activate menu bar with Alt. Alt + the underlined letter opens that menu or submenu.
Alt+Space opens the control menu for that window. In MDI apps, alt+hyphen opens the document's window control menu.
Then...
Alt+space, x = maXimise
Alt+space, n = miNimise
Alt+space, s = reSize followed by cursor key to select which edge, then cursors to change.
Hotkeys are Ctrl+letter and do that action now.
Ctrl+...
p = print
s = save
o = open
f = find
c = copy
x = cut (looks like scissors)
v = paste (looks like an arrow: paste _V_ HERE )
Shift modifies or reverses many commands, and selects while moving.
In dialogs and forms, Tab moves forwards; Shift+Tab backwards
Ctrl+PgDown = next tab
Ctrl+PgUp = previous tab
Ctrl+Enter = save and close form
Ctrl+left/right = move by word instead of character
Shift+home/end = select to start/end of line
Esc = cancel
Ctrl+Esc = open start menu
Then tab, and you're tabbing through the taskbar, which is a sort of dialog box.
Ctrl+Shift+Esc = open task manager
Maybe this should be on a wiki somewhere so it can be documented collaboratively...