I've started reading this article on the history of the ThinkPad. In it, the TrackPoint (pointing stick/"nipple" mouse) is heralded as an important innovation in the design of portable computers at the time.
However, it doesn't mention what the alternatives were at the time; what the TrackPoint replaced. In those days where lots of PC software was still DOS-based I can imagine the alternative was no pointing device at all — but even back then, I'm pretty sure Windows was established enough that business users wouldn't have accepted that.
So, what pointing devices were used by early laptop computers?