LiveCode Platform - It is Both Under the GPL and it is also Proprietary if using the GPL version the software you make...

craigslist - craigslist provides local classifieds and forums for jobs, housing, for sale, services, local community, and events

Microsoft Office Access - Access is now much more than a way to create desktop databases. It’s an easy-to-use tool for quickly creating browser-based database applications.

Bedpage - Bedpage is a classified ad posting a website that comes as the alternative to Backpage and offers almost all the major services to post for multiple categories.

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).

Facebook Marketplace - Marketplace is a convenient destination on Facebook to discover, buy and sell items with people in your community.