Need a straight lines tool
The others are missing it too. Common, I know it's not that difficult to program...
Maybe you can use the "rule" methaphore:
1st: position the "rule" any angle on the canvas.
2nd: draw a stroke of any kind on either edge of the rule.
3rd: maybe you can simulate the effect of bumping on the edge... wow!
4th: Why not using any other "stencil", ex.: ellipses or custom shapes.
Voilą, just ideas.