Zoho Creator - Zoho Creator is a low-code application development platform that helps you build a custom, mobile-ready apps to run your business.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
MySQL - The world's most popular open source database
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
Google Sheets - Synchronizing, online-based word processor, part of Google Drive.