All I know is that the pen icon is p lol.
p/b = pen
e = eraser
u = box
g = fill tool
m = marquee tool
h = hand
x = switch layers
I literally pressed every single key on my keyboard, but I couldn’t find one for circle or line.
You can also press 1 - 9 for colors 1 - 9…
What do you mean layers?
I think it’s the feature where you can have two colours selected at once, and can switch between them with one click.