Filter Forge is – by quite a margin – the most powerful plug-in we've looked at here. That's because it's a tool for creating plug-ins, both generative texture-creation tools and effect filters.
“It's a powerful and logical way of creating effects that's relatively easy to learn by seeing how other effects are built. Creating filters from scratch is time-consuming, but for a wider user group, it's a great way to modify already-created effects.”
“Chief among my pleasures is Filter Forge, which I've been ranting (positively) and raving (voraciously) about ever since it entered my life.”
Resident Enlightenment Manager Linden Lab, makers of virtual world Second Life