If you are looking to build passive income or a business via plugins and app stores, here are some of app stores and plugin marketplaces I personally feel are ripe for the picking.

eCommerce & Website Builder

WordPress – https://wordpress.org/plugins/

Shopify – https://apps.shopify.com/

Squarespace – https://www.squarespace.com/extensions/home

Team Communication & Project Management

Slack – https://slack.com/apps

Atlassian – https://marketplace.atlassian.com/

Monday.com – https://monday.com/marketplace

Zoom – https://marketplace.zoom.us/

Customer Support & Communication

Intercom – https://www.intercom.com/app-store

Zendesk – https://www.zendesk.com/apps/