Cron - Cron Calendar.
Qualys - Qualys helps your business automate the full spectrum of auditing, compliance and protection of your IT systems and web applications.
zcal - zcal is the fastest way to schedule every meeting for Free and make it personal.
Burp Suite - Burp Suite is an integrated platform for performing security testing of web applications.
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.
OpenVAS - The Open Vulnerability Assessment System (OpenVAS) is a framework of several services and tools...