Of course, it makes sense to set the priorities

Thanks for letting me know. Removed it from the gogmix, but am going to post a slightly modified version of the entry here, because it mentions where versions in other languages are:

Vikings: Wolves of Midgard
The manual is at http://cdn.akamai.steamstatic.com/steam/apps/404590/manuals/Vikings_Manual_PC_UK_ONLINE.pdf. For other languages: replace the UK in the url with FR, DE, IT, ES respectively.

It appears the Trine replacement manual link is failing, at least for me it is.
http://img.metaboli.fr/products/trine/en/user_manual.pdf

Fixed.
https://www.gog.com/forum/general/release_warhammer_40k_sanctus_reach_armageddon_2bda8/post50

Ah, that's good to know. Removed the manuals from my gogmix.

All metaboli links are dead unfortunately. I'm hoping it's only temporary.
Thanks. Removed.

Just added to my gogmix the manual for the newly released Ultimate General: Civil War.

P.S. Its layout might fool you, because it looks a bit lackluster (as if they printed a Word file or something), but the information it contains within is very detailed, so it counts as a real deal manual imo.

Hmmm... seems a borderline case. I'm generally against adding guides and keeping this for manuals only, however seeing how the info contained is actually "manual" info, as opposed to guides containing extensive details, and the fact that it's a pdf, as opposed to a wiki for example means I'll include it.

Not sure if you want to move this to Appendix B or not, but according to SpiderFighter, there is a manual (of sorts) in the game directory. I presume it's pretty much the same info that's in the PDF version, just in HTML form.

And done.

Just added the manuals for the newly released Lego Indiana Jones 2 and Lego Pirates of the Caribbean to my gogmix.
In regards to the second, I link to a copy I put on my Google Drive, because the link I found it from had me waiting 30 seconds and then had me solve 2 image captchas ("Choose the tiles that are street signs"), which means it is somewhat annoying to get the manual from there (and there's also the chance Chrome and Firefox might flag the site at some point as unsafe).

Updated.

Battlezone: Combat Commander lacks a manual.

You can find one for the original version below:
https://vignette.wikia.nocookie.net/battlezone/images/1/1e/Bz2_manual.pdf/revision/latest?cb=20131112143918

The link takes you to Battlezone 2 manual. How is that game different from the 2018 version?

EDIT: OK, I see the 2018 version is a remaster. So it's like Full Throttle and Turok? The remaster version didn't come with a manual, but the original manual is still applicable?

It's the same game, but with revamped visuals.
Pretty much.
While they might add a revamped manual later on (just like they did with the remaster of the first game), information about the game's units, build trees and general how-to-play should still be applicable.