A couple of suggestions for removal from the list: Botanicula DLC
"The Humble-exclusive bonus content showed up 5 years later without a free upgrade for GOG users."
This was never free DLC on any store. It's part of a higher-priced edition on Humble, and separate paid DLC elsewhere.
It *was* part of the launch day Humble Bundle, but that fiasco only affected people who'd pre-ordered Botanicula, and they received the bonus content (along with Machinarium and The Witcher) at the time to make up for it. Adding this DLC to GOG redressed the issue of it being unavailable here - it seems wrong to criticize Amanita for not making it free just because it was available cheaply in a Humble Bundle 6 years ago. The Final Station
"Missing Collector's Edition"
We have this. As the Steam page
shows, the Collector's Edition is just a bundle of the base game and its two DLCs ("Art Book & Soundtrack", "The Only Traitor") with a 10% discount. GOG has exactly the same offer. It was advertised in the news release
for The Only Traitor. It's also shown on The Final Station's game page
, but good luck finding it. GOG's new layout makes bundle deals like this practically invisible by calculating the discounted price and putting it in a greyed-out font under the "Why buy on GOG.com" section. Sigh.