IDE

Altair GraphQL Client
GraphQL IDE with many helpful features, available for multiple platforms.
Apollo Studio
A cloud platform that helps you build, validate, and secure your organization's data graph.
GraphiQL IDE
An extensive IDE for exploring GraphQL API's
Insomnia Core
Desktop client for REST and GraphQL APIs.

Fuji X
WYSIWYG platform that lets create
 a backend for your product in minutes.