I recently picked up a Macintosh Display Card 8*24 GC NuBus video card. The one thing I immediately noticed is how hot the Am29000 CPU got. I was looking for an inexpensive passive cooling solution and this is what I came up with. I found this 4 pack of aluminum coolers for $10.99 on Amazon. I attached one of the coolers to the Am29000 using Sekisui #5760 double sided thermal tape. This has made a noticeable difference in how hot the Am29000 now gets. Attached is a photo of how this looks on the Macintosh Display Card 8*24 GC and a link to the coolers on Amazon.
https://www.amazon.com/dp/B07SMX1DB7?psc=1&ref=ppx_yo2ov_dt_b_product_details
https://www.amazon.com/dp/B07SMX1DB7?psc=1&ref=ppx_yo2ov_dt_b_product_details