It would be cool if we could paint lines of tiles by holding ctrl or some other key while dragging with the paint tool. 
You can draw lines of tiles with the Rectangle tool. Yes it might be cool to have a shortcut key.
Straight lines, yes. This is what Iām looking for.
aaah yes! Ok got it. Yeah that would be cool. Like a typical line tool. I think I must have blocked it out of my mind. I usually get annoyed with pixel line tools in getting the line I want, I most of the time click out a segment then copy-paste building up the line. But definitely something to consider.
Cheers
Im looking for the same. Holding shift and be able to draw a straight line is a must.