Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
LibreOffice - Base - Base, database, database frontend, LibreOffice, ODF, Open Standards, SQL, ODBC
Ragic - World's most advanced online database engine. Build powerful online databases with simple Excel style online interface.
My Visual Database - Using My Visual Database, you can create databases for invoicing, inventory, CRM, or any specific purpose.
Zoho Creator - Zoho Creator is a low-code application development platform that helps you build a custom, mobile-ready apps to run your business.
MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.