In Cohorts We Trust - A straightforward template to build cohorts for marketplaces

Cocorico - Cocorico is a state-of-the art Open Source solution to create an Airbnb or Blablacar for anything.

RemoteIndian Job Board - A remote job board for devs based in India

Sharetribe - Build your online marketplace business. You don't need a developer.

GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.

JaJuMa-Market - All-In-One Multi-Vendor / Online Marketplace Solution. Various Business Models supported.