SheetKeys by Phil Crosby

If you are a project manager, programmer, finance person, or just someone who uses spreadsheets a lot, this can greatly increase your efficiency in Google Sheets.

After installing, you can see and customize all of the keyboard mappings by typing "?" while on a Google Sheets page.

Here is a partial list of shortcuts, and their default key assignments:

Movement:

j Move cursor down
k Move cursor up
h Move cursor left
l Move cursor right

<C-J> Move rows down
<C-K> Move rows up
<C-H> Move columns left
<C-L> Move columns right

<C-d> Scroll half page down
<C-u> Scroll half page up
g,g Scroll to the top of the sheet
G Scroll to the bottom of the sheet

Selection:

v Begin selecting cells
V Begin selecting rows
A-v Begin selecting columns

Editing:

i Edit cell
a Append to cell (edit but, starting at the end)
u Undo
<C-r> Redo

o Insert a row below the cursor and edit it
O Insert a row above the cursor and edit it
s Insert a row below the cursor
S Insert a row above the cursor

d,d Delete the current row (or selected rows/columns)
x Delete cell contents
y,y Copy the current row (or selected rows/columns)
y,c Copy cells
p Paste

Formatting:

;,a,l Align left
;,a,c Align center
;,a,r Align right
;,w,w Wrap cell
;,w,w Overflow the cell
;,w,c Clip the cell

Other:
? Show the help dialog
;,w,f Toggle full screen
;o Open URL in cell in a new tab