Contact your local school districts guidance office- seriously. They either know of programs that the school district already has in place (and you can look into volunteering) or they can pass on your phone number when they encounter a parent who is looking for someone. I know that right now, parents are looking for shadows for summer camp if you are willing/able to do that.
I found my (former) steady job through an adaptive swim program- I was teaching swim lessons to a little girl with cerebral palsy. It took time to show mom that I was capable (lifting, toileting...) before I started babysitting. The end of that story is that the "little girl" is a teenager and we still keep in touch even though we are many states apart!