|Is fifth-edition Warhammer considered Oldhammer? It's from two decades ago, so I'm gonna say yes.|
The Battle Book includes brief overviews (and lotsa photos) of the various forces of the Warhammer world. It also has rules and stats for many of the races, beasts, and monsters. There's also a short section on running campaigns, which can be adapted to other games as well. Who else has scored something vintage from a used book store recently?