Airportal - Instant customer portals from your Airtable base
MarketplaceKit - MarketplaceKit is a platform for building different types of online marketplaces.
Airtable Universe - Real workflows from real people
JaJuMa-Market - All-In-One Multi-Vendor / Online Marketplace Solution. Various Business Models supported.
Stripe Billing Customer Portal - Stripe-hosted page for customers to manage subscriptions
Sharetribe - Build your online marketplace business. You don't need a developer.