Part time 135 is doable. Mostly if you are close friends with the owner and he makes up a job specifically for you.

Or part 91 flights, if you know the business owner.

Or jumpers and glider towing.

It is more about who you know than what is available.

As an instructor I had a part time 135 job flying 2 days a week. Because I was at the airport all the time and knew the owner, and he knew I would fly fairly cheaply.

It's more about being in the right place at the right time.

If anyone tells you it can't be done, go out and do it.