Press A for color Press Q for grayscale Press E for Eraser Press S to toggle on/off grid snap Press G to show the grid Press X and Z to increase/decrease the color value. Press N and M to increase/decrease the brightness value. Press O to toggle on/off offset. Press B to show/hide the color and brightness variables (if you want to change them faster).
I got the grid-snapping from FUNUT (Professor Blue on youtube) but other than that I did the coding myself. Please go check out his youtube channel and scratch profile!