Freebie DSP for VST, AAX and Audio Units
My pal Warren Huart has added a neat episode to his Produce Like A Pro video series where he demos a selection of free plugins - check it out!
Another interesting freebie is the PSP PianoVerb, which aims to emulate the sympathetic resonance of piano strings... if you have a lacklustre digital piano sound, give it a whirl! . . .