Simple on screen ruler for drawing completely straight lines. I’m laying a physical ruler on top of the iPad screen to do it.
A good method. Bought a soft ruler for my Cintiq ages ago. Those days a bunch of simple things where missing in almost any app.
But I would prefer to have a bunch of basic forms available in stroke menu.
Line, arc, ellipse, square, poly.
All of them floating and editable, with a stamp function.
Drag a line, place it, stamp, move a bit more, stamp, move rotate, stamp.
Same for any other shape. Even poly lines. Available for any brush or tool.
Together with tiling, this would be a killer function!
You can try that in Infinite Painter. Regarding Design tools it is way ahead of any drawing app I know.