Depends on your hobbies. I'm into cybsec, there's a ton of small events where you can either be on stage (so submit a proposal), but there is often what we call "rumps" which are usually unplanned 5 minutes talks about a subject. They're a great way to practice.

Besides that, i guess schools/student groups that seek professionals. Non-profits works as well, I did that when I was younger (advocacy).