Just walking or driving around town. I've helped a couple get a refrigerator in their house - somehow the delivery service left it in their driveway. Weeded without asking - parking strips, or other parts of property not near the windows or house. I'm always on the lookout in winter for a stuck car that needs shoving.
Since it's Spring, offer to help older folks get their garden going. Once things are planted they can usually manage well enough.
If you live where people dig pools often, sometimes it's easier to shovel than Bobcat - noise issues with neighbors, restricted space, etc. Excellent work if you can get it.
Neighborhood websites around here usually have someone asking for some sort of physically demanding help. Today, for example, someone is asking for help clearing their 10 acre property of limbs that fell off during the winter storms. One could not only pile them up but also bow saw them into kindling.
how/where do you find such work ?