Warhammer Digital Goodie Pack which includes Warhammer: Shadow of the Horned Rat for free amongst other freebies such as
A batch of cool Warhammer Skulls and Adeptus Titanicus: Dominus wallpapers.
A World Eaters sampler from The Black Library in PDF, epub, and mobi.
A free Warhammer 40,000 Roleplay Adventure titled Rain of Mercy in PDF.
A Warhammer: Mark of Chaos – The Collected Concept Art album in PDF.
An original soundtrack from Warhammer 40,000: Mechanicus in FLAC and WAV.
A 15% off discount code for Warhammer merch (valid until 31st August 2021 for use in the official store)
As part of Warhammer Skulls event.
Available until the 10th of June 2021 https://www.gog.com/news/join_the_warhammer_skulls_event
Go go go!