Yes, I went hunting around for filter plugins again. All sets but one are free downloads. I've only included one example per plugin site, but linked to a number of others (hopefully that way the dial-up users won't be pulling out their hair while waiting for the page to load.)
I use PSP 7 and PSP X, and all of these filters work in Paint Shop Pro as well as Photoshop. The only exception to this is Filter Forge, which does NOT work in PSP 7. However, it also functions as a stand-alone app, so that's not really an issue.

A whole bunch of freebies here, most of which aren't particularly useful, but I really like the Fine Threshold filter (and the end result also colorizes very nicely):

Several filters here -- most of them pretty basic -- but one that's useful is the background gradient blur:

They offer a freebie filter called virtualPhotographer, which does a bunch of stuff, among them effects like this one:

Other examples: Reminiscing || Spice || Slight Grain
I had a fine time playing around with Filter Forge. This one, alas, is not free, although you can mess around with it for 30 days with no restrictions. The plugin filter library is incredible:

Example-O-Rama: Bullet Holes | Burninator | Chalk | Charcoal Drawing | Charred Pages | Comic Book | Comic Stylize | Forgotten Poster | Gouache | Grunge | Icicle Works | Ink and Paper | Manga Kata | Marbelizer | Old News | Unfolded Poster
Whew. There's many, many other effects and textures, so it was definitely worth the price tag imo.
I didn't keep these filters after downloading and trying them out -- once I bought Filter Forge, I knew I didn't need them -- but there's a couple of nice artsy freebie filters here.
(( Plugin Post #1 • Plugin Post #3 ))
I use PSP 7 and PSP X, and all of these filters work in Paint Shop Pro as well as Photoshop. The only exception to this is Filter Forge, which does NOT work in PSP 7. However, it also functions as a stand-alone app, so that's not really an issue.
Original Image
Mehdi Filters
A whole bunch of freebies here, most of which aren't particularly useful, but I really like the Fine Threshold filter (and the end result also colorizes very nicely):
Photo-Plugins
Several filters here -- most of them pretty basic -- but one that's useful is the background gradient blur:
optikVerve Labs
They offer a freebie filter called virtualPhotographer, which does a bunch of stuff, among them effects like this one:
Other examples: Reminiscing || Spice || Slight Grain
Filter Forge
I had a fine time playing around with Filter Forge. This one, alas, is not free, although you can mess around with it for 30 days with no restrictions. The plugin filter library is incredible:
Example-O-Rama: Bullet Holes | Burninator | Chalk | Charcoal Drawing | Charred Pages | Comic Book | Comic Stylize | Forgotten Poster | Gouache | Grunge | Icicle Works | Ink and Paper | Manga Kata | Marbelizer | Old News | Unfolded Poster
Whew. There's many, many other effects and textures, so it was definitely worth the price tag imo.
Little Inkpot
I didn't keep these filters after downloading and trying them out -- once I bought Filter Forge, I knew I didn't need them -- but there's a couple of nice artsy freebie filters here.
(( Plugin Post #1 • Plugin Post #3 ))

Comments
Basically...well, I'm lazy, so I luv my plugin filters. ;)
I've downloaded several brushes, many of the yours (thank you!), but I'm having trouble importing them. I've looked all over PSP help and my books, but find nothing about it.
Here's the problem: When I try to import the brush I get the following error: 'A file with the name "blah_blah_blah" already exists. Please choose another name.' However, it doesn't allow me to rename anything. I tried going back and renaming the brush file name, but get the same error. It happened when I tried to import your Old Alphabet brushes. They finally loaded when I used the .jbr file.
But many of the brushes I'd like to use don't come with a .jbr file. Is there some way I can create one from what they've given me?
If you'd prefer to answer by e-mail, you can at "brattfan [at] comcast [dot] net.
Thanks.
I make the pspBrush extensions in PSPX, so they might not be importable into PSP 8 or PSP 9, and pspBrush files don't work at all in PSP 7.
In PSP 9, X, and XI you can import the older JBR format brushes (not sure about PSP 8.)
Most brushes I see are in ABR format for Photoshop, but resource makers generally provide an image pack for those who don't use Photoshop.
Like me; I'm happy with my PSP. :)
Anyway, in those cases, I just take the image pack and make the brushes from that -- it's easy to do; just follow the instructions in your program's Help menu.