Shortcircuit
Been using this free sampler for a while now, pretty good for sound design stuff and suits the way I work quite well. I like the fact it is designed to be good at mangling audio and comes with NO library, it's not under development anymore unfortunately though.
http://vemberaudio.se/shortcircuit.php
I found this and some other stuff from this blog, which has loads of free and cheap plugins etc.
http://bedroomproducersblog.com/















