MarketplaceKit - MarketplaceKit is a platform for building different types of online marketplaces.
Facebook for Business - Facebook Business gives the latest news, advertising tips, best practices and case studies to meet the business goals.
JaJuMa-Market - All-In-One Multi-Vendor / Online Marketplace Solution. Various Business Models supported.
Buzzstream - Build Relationships. Build Buzz. Web-based software that helps the world’s best marketers promote their products, services and content.
Sharetribe - Build your online marketplace business. You don't need a developer.
Fomo - Fomo turns your site into the online equivalent of a busy store