From the Wirecutter: The best consumer-grade Wi-Fi extender
After spending a total of 110 hours researching 25 different Wi-Fi extenders (and testing 10 of them), plus analyzing reviews and owner feedback, we found that the $100 Netgear EX6200 is the best Wi-Fi extender for most people right now. It costs as much as a great router and it shouldn't be the first thing you try to fix your Wi-Fi range, but it has the best combination of range, speed, flexibility, and physical connections of any extender we tested.
In our tests, the EX6200 could stream 1080p YouTube videos to three laptops at the same time (one up to 63 feet away), and it was the only extender we tested that could stream a 4K YouTube video to a single laptop, outside the house, at the same distance. The Netgear EX6200 had the best long-range performance of the extenders we tested (35.4 Mbps), even through exterior walls. It was the easiest to configure, and because it's an AC1200 wireless-ac extender, it supports the fastest connection speeds of dual-stream Wi-Fi devices.
