I quite like PostworkShop
PostworkShop is a stand-alone program for Windows and Mac which is essentially a ton of filters which you can apply to images. It’s like Photoshop, only without the Photoshop. Except it’s a bit cleverer than that as you can customize, fine-tune, overlay and generally do lots of filter-Photoshoppery things with the filters too, including (with the more advanced versions) making your very own filters which you can share, sell and exchange. Or something.
What I like most about it is that it’s fun. Start a new project, load in an image and hit the filters until the little man in your head says “Ooo, I quite like that!” and save it. Job done. The demo version gives version gives full access to all 350+ filters and the entire build-your-own interface (but adds a watermark) but it’s a matter of seconds to get a free serial number which magically turns your demo app into the fully fledged Basic Edition. This gives you 50 filters to play with and no watermark. That’s an ingenious choice – unrestricted-but-watermarked or limited-but-complete – and it gives you a good taste of the app as a whole. It’s pretty likely that you’ll never need to migrate from the free, Basic Edition at all. The Artistic Edition (350+ styles, can create your own free Styles) is $49, while the Pro Edition (create commercial Styles, Batch Processing) is $99.
Enough of that though. Here’s a few examples of my own humble messing about. These all started life as bog-standard DAZ Studio renders. Enjoy.