4D - 4D is a relational database management system and IDE.
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
LiveCode Platform - It is Both Under the GPL and it is also Proprietary if using the GPL version the software you make...
Zoho Creator - Zoho Creator is a low-code application development platform that helps you build a custom, mobile-ready apps to run your business.
ESM Tools - ESM Tools is a powerful and widely known software development platform that comes with a centralized model infrastructure, providing the common frame for compiling, running, downloading, and organizing models (ones or multiple).
QuickBase - Quickbase provides a no-code operational agility platform that enables organizations to improve operations through real time insights and automation across complex processes and disparate systems.