RAMA....QIN....SPQR.

What is the criteria for inclusion on GOG?

A handful of darts and a monkey spun on a barstool.

But perhaps phrased more clearly, what does your question mean?

I apologize....I am new here. I was referring to those 3 obscure adventure games. I found the wishlist section, and voted accordingly.

Well, RAMA was release by Sierra, so its rights should be property of Activision. The problem is that it was an unknow game for most people, but who knows. Recently they release on gog Shivers Two.

There's more: EcoQuest series, Manhunter series (only published by Sierra), Mixed up Fairy Tales, the old Disney adventures, Gold Rush (available on Steam), Inca, Lost in Time...

You are right. I overlooked a decent sized list. Anyway I do not see any problem with them for have them eventualy available in GOG, maybe except the old disney IF adventures. In theory.

Damn...I have a mint boxed copy of SPQR. Maybe i should play it one of these days. The old adventures I'd like to see are the historical mystery games from Cryo Interactive, like Versaille1685. Probably all too niche they days.

Not only those, but even the Hi-Res Adventure series which started the whole Sierra adventure thing is missing.

Of course, most of those games were made before the company changed its name to Sierra, so it's a bit debatable whether those qualify as Sierra adventures, but still they are made by the same company.
And obviously none of them are hi-res, so there's that too!