ILLA Design

Summary
ILLA Design offers a fully responsive UI library for React. It provides pre-built components and a drag-and-drop interface for building user interfaces. This allows developers to quickly assemble interfaces for their applications.
Rationale
ILLA Design is a React UI library, which aligns with the 'Drag-and-Drop UI Builder' and 'Prebuilt React Components' features. The website content explicitly states it's a 'fully responsive UI Library for React'. However, it doesn't obviously provide the full scope of features expected of Retool, such as database integrations, security, or deployment options. Therefore, the confidence is moderate.
Features
Must Have

Drag-and-Drop UI Builder

Other

Prebuilt React Components