The rights to this series are now with Warner Brothers, along with virtually all of Midway's games. The rest are currently being disposed of by the Midway Liquidating Trust: http://dm.epiq11.com/MWY/Project Nectaris (aka Military Madness)
The rights are now with Konami. Wolf
Sam Palahnuk, who worked on the game, believes that the rights are no longer held by any company. https://twitter.com/sampalahnuk
I would first check with others who worked on the games, like Ivan Manley of Manley & Associates. This person seems to have gotten into contact with Mr. Manley recently: http://www.thebrothersduomazov.com/2013/02/heroes-of-midnight-sun-manley-associates.html The Lost Vikings 1 + 2
We would need to check with both Blizzard and Interplay to see who holds the rights to which properties. Nippon Safes
As for this and other Dynabyte titles, Paolo Costabel of Dynabyte could know what happened. He's well connected so it's easy to find his LinkedIn, Google+, etc info. I found this e-mail address, but it's about 9 years old:
paoloc(at)pacbell(dot)net Nobunaga's Ambition 1 + 2
Tecmo Koei's got tons of great strategy games in addition to this, and it would be awesome to see their stuff on GOG. Getting in contact with them (and waiting for the heads in Japan to decide on anything) is the tricky part.
Regarding Dinamic Multimedia's library, it's worth asking the Ruiz brothers at FX Interactive if they know what happened. http://www.fxinteractive.com/int/us/contact.htm Powerslave/Exhumed
Mentioned this elsewhere, but the developers, Lobotomy Software, think that Activision last held the rights to the game: https://www.facebook.com/permalink.php?story_fbid=501683913235556&id=386374664766482
I asked Infinite Game Publishing (of the online Mechwarrior games) if they had the rights to any of the older Mechwarrior games, but they say that they don't. Even if they did, some of those games used mech designs that they no longer have the rights to, so that would be a huge problem.
The Chaos Engine remake developers intend to release the game on GOG, so that hopefully covers the original game, but Bitmap Brothers is only sort-of involved. Don't know why they've ported Z to smartphones but haven't re-released it on PC. Tried e-mailing them twice but never got an answer. Others can try here: http://www.bitmap-brothers.co.uk/contacts/index.htm Heart of Darkness
Eric Chahi ought to know what happened to the rights to the game. I know he co-produced the game with 4 others: Frédéric Savoir, Fabrice Visserot, Daniel Morais, and Christian Robert (deceased). He has a LinkedIn site, but I have no idea how to search for the company he works for now - °0° http://www.linkedin.com/pub/eric-chahi/10/a52/71b
He used to have a personal site, anotherworld.fr, but his email there is now dead. Blade Runner
We need to ask the current rightsholders to the Blade Runner name, the Blade Runner Partnership. Others have had success getting in touch with them about other topics related to Blade Runner, but they never replied to me about the game: http://www.alconent.com/contact/contact-form Chasm: The Rift
I can't find Igor Karev's contact info (he handled the business side of the development company). Last I know, they worked on Cryostasis and shortly afterwards disappeared. Other developers who worked on the game now work at Tatem Games, but no one there's answered any of my e-mails: http://tatemgames.com
/ Veil of Darkness, The Summoning, War Wind, Dusk of the Gods, etc.
I want to ask the producers of Event Horizon Software/DreamForge Intertainment if they know what happened to the rights to these older titles. I know we have Anvil of Dawn and Sanitarium here, but each are from separate publishers. If these guys don't have those rights, hopefully Ubisoft or XS Games have them and can bring them to GOG. Anyway, the three producers (James H. Namestka, Christopher L. Straka, and Thomas J. Holmes) are now part of a company called Donohue Partners in Greensburg, PA. http://www.bizapedia.com/pa/DONOHUE-PARTNERS.html
Unfortunately, I can't find their contact information (for free anyhow), only snail mail addresses.
They also did Dungeon Hack, but that being a Forgotten Realms licensed work, they wouldn't have the rights to publish it.
Edited for some clarity.