Prah: Kingdom series (Noio):
Kingdom Two Crowns

Prah: Blitzkrieg series:
Blitzkrieg 3

Grargar: The section can be removed, as the game has been released here.
https://www.gog.com/game/kingdom_two_crowns

In addition:Grargar: Blitzkrieg 3 requires a constant online connection even for single-player, which should disqualify it from the list.

Alexim: I don't know if they count, but Minit Fun Racer is missing on GOG.
In addition, Devolver Bootleg and Devolverland Expo also have links to Devolver games featured on GOG.

Swedrami: SKYHILL: Black Mist (Wishlist entry), the sequel to SKYHILL has yet to be released on GoG as well.

Grargar: Flight of the Amazon Queen: 25th Anniversary Edition was released on Steam some days ago:
https://store.steampowered.com/app/1105460/Flight_of_the_Amazon_Queen_25th_Anniversary_Edition/

In addition, the first Samorost got a free non-flash rerelease on Steam and itch.io:
https://amanita-design.net/games/samorost-1.html

Grargar: Door Kickers 2: Task Force North has been available on Steam Early Access for a while:

https://store.steampowered.com/app/1239080/Door_Kickers_2_Task_Force_North/

tap3ah: Warhammer: Battle March should be removed, since it's expansion for Mark of Chaos, and is included in Warhammer: Mark of Chaos - Gold Edition. Maybe the confusion came from the fact that XBOX version of the game was rebranded as Battle March (see [url=https://en.wikipedia.org/wiki/Warhammer:_Mark_of_Chaos]here[/url]).