Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.

go-catchup - Friendships are important to you, but sometimes life gets in the way!The go-catchup add on for Google Workspace™ reminds you to regularly catch up with a large group of friends - one friend at a time

Facebook Local - Discover places to go and events happening near you

Down To Lunch - Press one button to get lunch with friends

Eventbrite - Discover Great Events or Create Your Own & Sell Tickets

PotluckHub - Simply plan your get-together