I definitely recommend in person service. My experience has included habitat for humanity, engineers in action, local food pantry, stem events like public museum festivals or school competitions like science olympiad and future city, etc...
I'm kind of introverted so I show up and just focus on staying busy and finding work to do to help, but often end up meeting interesting people I might not otherwise meet. It kills the time and I get to do something good for others.
Just sign up for stuff and go do things, you never know what will come of it!