Postcrossing - A postcard exchange project that invites everyone to send and receive postcards from random places in the world. For free!
Bumble - Bumble is a social network that allows you to feel empowered while you make those connections, whether you’re dating, looking for friends, or growing your professional network. One first move on Bumble could change your life.
swap-bot - Swap-bot is a online service that organizes group swaps and a community of creative individuals.
Tinder - Tinder is how people meet. It's like real life, but better.
Random PenPals - Get a quarantine PenPal in 10 seconds
Hinge - Find people you want to date through your friends on Facebook.