You could try looking at United Way's site to see if anything pops up that sounds interesting to you.
I volunteer as a wildlife rehabilitator (I work with small animals like squirrels and opossoms, but they take in bunnies, birds, reptiles and amphibians, etc.)
I also work with a therapeutic horse riding program geared towards children with disabilities. I primarily do the horse stuff (clean stalls/water buckets, groom & tack, lead horse), but they also use folks to work with the kids themselves.
Could look into running something class-like at your local country library. I am the alternate lead for a yoga class I started taking there (for free) years ago, and I love yoga... I just stress I'm the substitute teacher, I am not trained, just enjoy doing it so anyone else that wants to do it when the instructor is out is fine to join in. But they offer sewing, language, coding, even financial stuff because there is someone willing to volunteer their time and expertise to teach a regular class there.