The best Router Custom Firmware alternative to OpenWrt is DD-WRT, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to OpenWrt and seven of them are Router Custom Firmwares so hopefully you can find a suitable replacement. Other interesting Router Custom Firmware alternatives to OpenWrt are OPNsense, MikroTik RouterOS, Freshtomato and PiFi.
OpenWrt alternatives are mainly Router Custom Firmware, but if you're looking for
Firewalls or VPN Services you can filter on that. These are just examples - use the filter bar below to find more specific alternatives to OpenWrt.