Key features of Wi-Fi extenders include extended coverage to eliminate dead zones, dual-band support for 2.4GHz and 5GHz frequencies, an Ethernet port for wired connections, adjustable external antennas, easy setup via WPS or a mobile app, advanced security protocols, and high-speed performance to improve streaming and gaming experiences. Some models also offer features like parental controls, guest networks, and smart roaming for seamless device connectivity.