Wacom Intuos GD
The original GD has an official driver only through 10.6, but worked fine through 10.9. As of 10.10, it no longer worked and hung the computer on startup. Could only boot with tablet disconnected. Tried updating to Intuos driver for 10.10. Then could boot ok, but driver did not install properly and tablet did not work. Only solution was to load the driver 6.2.0-w4 for Intuos2 that is officially supported through 10.7. This driver’s preference pane will no longer open, so configuration options are not accessible. But at least the system boots and the tablet works again. It is clear Wacom could provide a working driver with minimal fuss, but would prefer to try to obsolete older products to force upgrades. Bad Wacom.
Since this was the first free OSX upgrade, I grabbed it and updated my trusty Snow Leopard configuration. Miraculously, everything just worked. What a sweet surprise.