On mac, ⌘ can be used in place of CTRL

Card Selected

CTRL + C Copy card
CTRL + V Paste card
CTRL + O Open card
CTRL + N Create new card
Arrow keys Move to the next card
Start typing Starts editing the card
ALT + Arrow key Moves the card
ALT + Drag Duplicates the card/text/image
CTRL + SHIFT + Arrow key Copy and pastes the card
SHIFT + Arrow key Change color of the card
DEL Deletes the card

Editing Card

CTRL + A Select all of the text on the card
SHIFT + Enter Add a new line to the card
ALT + Enter Add a new line to the card
Esc Cancel changes made to the card
Enter Accept changes made to the card

General

? Show keyboard shortcuts
ALT + S Share board
CTRL + F Search
CTRL + Z Undo
CTRL + Y or CTRL + SHIFT + Z Redo
CTRL + + Zoom In
CTRL + - Zoom Out
CTRL + Mouse scroll Zoom In/Out to mouse position
z Fullscreen mode for card details

Card Open

CTRL + S Saves changes made to the card
Esc Cancel changes made to the card
CTRL + I Edit card title
CTRL + D Edit card description
z Fullscreen mode for card details