Once the bambino is crawling, you’re pretty much kicked out of postpartum yoga. Consider a local gymnastics studio — they usually have Parent & Tot classes in the mornings when big kids are in school.
Franchises like My Gym, Gymboree, Great Play, and The Little Gym also offer Parent and Child classes, often for as young as 4 months old. The chains usually have a free trial class, so be sure to do that.
When you research your options (search “mommy and me gymnastics” and your city’s name), look out for the benefit of membership entitling you to access drop-in times. To me, this is appealing for rainy days when the living room is getting tiresome.