OpenWrt - OpenWrt is an open-source firmware based on Linux for wireless routers
Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
MikroTik RouterOS - The main product of MikroTik is a Linux-based operating system known as MikroTik RouterOS.
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
Be Focused by XWaveSoft - Simple Pomodoro timer in your Mac's menu bar