OpenWrt - OpenWrt is an open-source firmware based on Linux for wireless routers
F-Droid - F-Droid is an interesting alternative for Android users who want to try something different and not have to use the Goole Play store all the time.
MikroTik RouterOS - The main product of MikroTik is a Linux-based operating system known as MikroTik RouterOS.
APK Pure - Download apk for Android with APKPure APK downloader. NoAds, Faster apk downloads and apk file update speed. Best of all, it's free
pfSense - pfSense is a free and open source firewall and router that also features unified threat management, load balancing, multi WAN, and more
APKMirror - Android Market and APK Downloads