Holly Website Audit - Free, brandable website audit for your potential clients
speedtest-cli - Test your download speed using SpeedTest on the command-line
Website Grader - Grade your website's strengths and weaknesses in seconds.
Global Website Speed Test - Test website load speed from 18 cities, including 3 in China
Website Speed Ranker - Compare how fast your website loads vs your competitors
Speedtest by Ookla - Measure your ISP's performance in a click