Literally anyone you see regularly see. Make light eye contact and smile. After a couple times seeing the same person just try something simple:

" I see you here often. Do you know ______?"

A: Yes/ "Ya they have been coming here since _____. I started back in ________."

B: No/ "Oh, well I'm ________ it's a pleasure to meet you."

You are planting seeds of discourse. It makes you more approachable.

I have engaged you here in good faith so I'd appreciate the same in return.