Docker Hub - Docker Hub is a cloud-based registry service

MockAPI - MockAPI lets users mock up APIs, generate custom data, and perform operations on it using RESTful interface.

Pneumatic - Pneumatic is an SaaS workflow management system designed to make business process management easy and accessible to everyone. Pneumatic emphasises ease of use, iterative development and continuous improvement of business processes.

Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.

Sandbox - Tax compliance APIs for India

Mocki - Using Mocki you can create, run and deploy mock services without hassle. Use your mock services to run tests independent of external services, design APIs and remove backend dependencies for your frontend team.