It’s unique: there’s an Apple FireDrill card on eBay. This PCI card was never officially released (dating back to 1997) and was intended to accelerate audio and video processing with dedicated chips (32-bit processors clocked at 100 MHz).
The main feature of the card is that it adheres to the FireWire 200 standard (25 MB/s), whereas the majority of devices typically use either the 400 or 800 versions. Rare tests indicate that the card indeed works with a « recent » Mac OS X (like Tiger) but only in 200 Mb/s mode. It’s worth noting that the connector is the same as that of FireWire 400 cards.
Mac OS X
Power Mac G3