iperf - A TCP, UDP, and SCTP network bandwidth measurement tool
Fast.com - Quickly test your internet speed with this fast-loading speed test powered by Netflix.
JPerf - This project gives a better UI and new functionalities to the initial JPerf 1.
SpeedOf.Me - SpeedOf.Me is an HTML5 Internet speed test. No Flash or Java needed!
netperf - Netperf is a benchmark that can be used to measure the performance of many different types of networking. It provides tests for both unidirectional throughput, and end-to-end latency. - HewlettPack...
LibreSpeed - Self-hosted Speedtest for HTML5. Easy setup, examples, configurable, mobile friendly.