UndoTwo-finger Tap (can be held)
RedoThree-finger Tap (can be held)
Switch between brush and eraserDouble Tap Pen
Cut/Copy/PasteThree-fingers Swipe
Eye DropperTouch-and-Hold
Color DropDrag the Active Color onto artwork (hold and slide to adjust tolerance)
Maximize CanvasQuick Finger-pinch
Hide UIFour-finger tap

One can draw a square, triangle, circle, line, arc, polygons and then not move the pen and procreate will make it to that shape. Then tap with finger to rotate in 15 degree angles. Hold down finger to turn into perfect shape.

Merge LayersPinch layers together with fingers
Duplicate LayerPull layer onto canvas
Move layer to other filePull layer and with the other hand switch to the document, then release the layer in layer menu
Hide all other layersHolder hide layer button
Alpha LockTwo-finger swipe right on layer
Multi Select LayersTap layer, then swipe right other layers
Layer OpacityDouble Tap Layer, then slide left or right
Select LayerTwo-finger hold on layer

When changing opacity, the farther you move the finger away from the bar, the finer the adjustment is.

Multitasking: Pull up, grab app and pull it onto the procreate window

Undo History = 256 Layers =