CakeHR - CakeHR by Sage is a one-stop-shop for your HR management needs. Your HR - simplified!
Absence - Employee vacation tracking system
Bitrix24 - Bitrix24 is a free (for small businesses) social enterprise platform. It is a united work space which handles the many aspects of daily operations and tasks. Create your own social intranet in minutes!
TimeOffManager - TimeOffManager.com provides a fully automated online system for tracking and managing employee absence, leave, paid time-off and attendance.
Timesheets.com - Time Tracking for Payroll and Billing
LeeveBot - Manage team leave with Slack.