Calendarix - Calendarix is a powerful and easy to use web-based calendar that runs on PHP and MySQL.
TestRail - TestRail provides comprehensive test case management for software testing. Organize your testing, boost productivity, get real-time insights, and track progress toward milestones. Integrates with leading issue tracking and test automation tools.
Cronofy - Unified Calendar API for developers
LambdaTest - Perform Web Testing on 2000+ Browsers & OS
ApPHP Calendar - ApPHP Calendar is a PHP calendar script that may be easily integrated and used with various PHP projects, such as schedulers, event, etc.
PractiTest - PractiTest is a cloud based Innovative test management tool.