(click here for download info) 
From the Elysia website:
“Its main function is to change the proportions between high and low frequencies. The principle is quite similar to a pair of scales: Dependent on the gain setting around a variable center frequency, the high frequencies are boosted whereas the low frequencies are attenuated (or vice versa) at the same time.”
(click here for download info) 
8 free plugins. Not just one; 8!
Blue Cat Audio has a bundle of free plugins available for download that include:
Whether or not they will be useful to you is really up to you, but at the price (FREE!) they are definitely worth a try.
(click here for download info)
Yet another “amp simulator”, but a fairly decent one. Simple controls (just like a real amp) and… it’s FREE! Useful for more than just guitar as well (vocals, crushing some drums, etc). A must have, in my book.
(Did I mention it was free?)
(click here for download info)
Drumcore Free is a “light” version of the full Drumcore product. It can be used as a “groove player” or as a triggered drum sampler. It includes only 2 drumkits (rock/pop and hip-hop), and is definitely a “tease” of the full product as it cannot be expanded or added to without puchase, but is still fairly useful.