What terminal-based network speed tests are available?

You may use nload (Install nload) for this purpose. Sample output:

You can install nload by this command:

sudo apt-get install nload

Also available in software center.

Update Nov 2016: I discontinued it. Please use another provider i.e. Init7 with http://speedtest.init7.net/10GB.dat

Original answer:

There is also this easy "speedtest":

wget -O/dev/null speedtest.pixelwolf.ch

This gives you the current speed and it is available up to 100 megabits per second.

How about netperf? http://manpages.ubuntu.com/manpages/maverick/man1/netperf.1.html

netperf

Quoting from the man page:

Netperf is a benchmark that can be used to measure various aspects of networking performance. Currently, its focus is on bulk data transfer and request/response performance using either TCP or UDP, and the Berkeley Sockets interface. In addition, tests for DLPI, and Unix Domain Sockets, tests for IPv6 may be conditionally compiled-in.