Cyan/n is a free Max app for creating sample based compositions by Katsuhiro Chiba. Development has stopped in 2008 but this is still cool. This is what you´ll get: Slicer · Looper · Rhythm box with 4 tracks granular · Multi effect and Master effect etc are integrated and can be processed in real time without stopping performance. The user interface is laid out so that you can quickly access all parameters, and it also supports external MIDI controllers. Site is is japanese.
The Mutated Texturizer and the Mutated TexturizerAlt are free Max For Live plugins from Timo Rozendal, based on the firmware for the eurorack module Clouds by Mutable Instruments.
Random Riff Generator is a midi tool by Mario Nieto that generates sequences for you. This is the free version.