Returnbase (reverse logistics), CropMetrics (agtech), Weather Analytics (ag. insurance), and Loop Support (customer support, shameless plug) come to mind.

It's tough to "casually observe" startups because you can't flip through their 10-Ks, but you can think of individual startups metonymously - learn more about their industries, and then try to figure out why these startups are trying to use technology to make better products.

FarmLogs and Flexport are two that seem neat from the outside (farming and logistics, respectively)