Try any bush or small tree for the layering.

For other propagation, some people do rose bushes over the few months of cold weather.

Do plants like coleus or petunia for early starts next spring.

Some succulents are good for overwinter propagation also.

Do you have an interest in potted tropicals/house plants? If so, there's a house plant forum here also. Like Purslanegarden said, now is the time I start taking cuttings of/repotting many "annuals" that are really tender perennials, to save inside for winter.

I just started doing African violets from a leaf. They start well in water.

Thanks. Some great ideas to get through the next 6 months!

I don't know what your winters are like but if you can keep Winter flowering Violas outdoors they are easy to increase by cuttings. If you buy a small number of plants each can provide multiple offspring.