I don't know anymore of any source that's better than the others, but the folks on this board are usually pretty good about having things, and there's always eBay... not nearly as much good NuBus loot on there as there was about 5 years ago, but that's progress :-/
Before you get a video card, think about what monitor you want to use. If you're using a monitor that will work with your onboard video, it's probably best to keep the onboard video. It interfaces to the Mac directly, instead of via slow NuBus. Only get a video card if you have a big modern monitor and want to do 1024x768 or higher.
Accelerated NuBus cards are like 10x faster than motherboard video at things like window dragging where the video card can cache pixels, but motherboard video is almost always faster at dynamic things like QuickTime and Marathon.
Before you get a video card, think about what monitor you want to use. If you're using a monitor that will work with your onboard video, it's probably best to keep the onboard video. It interfaces to the Mac directly, instead of via slow NuBus. Only get a video card if you have a big modern monitor and want to do 1024x768 or higher.
Accelerated NuBus cards are like 10x faster than motherboard video at things like window dragging where the video card can cache pixels, but motherboard video is almost always faster at dynamic things like QuickTime and Marathon.