So, GOG says there's 80 such bundle offers (Or maybe they meant 80 games in bundle offers). Well, I've found a couple so far, but I think we should make up a list for reference to other GOG members. Also of note, it looks like games that you already own won't be sold again at bundle price, so it's unlikely that most people will be able to see all of them depending on their game shelf. If you choose to jump in and get involved then great, if not oh well. And for newcomers, the bundle discounts only apply to a set that is purchased to completion.

The 11th Hour + The 7th Guest: 15% Off

Age of Wonders Series: 23.03% Off (Age of Wonders 1, 2, Shadow Magic)
Thanks to Adambiser

Alien Shooter 1+2: 16.61% Off

Alone in the Dark Set: 16.61% (One 3 game collection, one stand alone)

Aquanox 1+2: 33.31% Off

Arma Collection: 14.6% Off (Includes Cold War Assault, Gold Edition, Arma 2)

Atlantis 1+2+3: 23.03% Off

Baldur's Gate 1+2: 15% Off
Thanks to Rodrolliv

Blake Stone Series: 44.4% Off (Includes Aliens of Gold, Planet Strike, Rise of the Triad:Dark War)

Blackwell Bundle + Gemeni Rue + Resonance: 20% Off

Blood: One Whole Unit (1+2): 16.61% Off

Broken Sword Series: 35.66% Off (Includes games 1-4)
Thanks to Rodrolliv

Cannon Fodder 1+2: 16.61% Off

Capitalism Plus, 2: 18.71% Off

Commandos 1-3: 18.71% Off (Includes Ammo Pack, 2+3 in a two game set)

Constructor + Mob Rule: 10% Off

Creatures Collection: 16.58% Off (Includes Exodus, The Albian Years, Village)

Crusader Series: 16.61% Off (Includes No Remorse, No Regret)

Cultures Collection: 24.97% Off (Includes Cultures 1+2, Cultures: Northland + 8th Wonder Of The World)

Dark Reign 1+2: 18.71% Off

Darwinia + Defcon + Uplink: Hacker Elite + Multiwinia: 44.41% Off

Deponia 1+2: 12.48% Off

Deus Ex 1+2: 34.98% Off

Dungeon Keeper 1+2: 16.61% Off

Eador: Genesis + Masters Of the Broken World: 11.51% Off

Earth 2140, 2150, 2160 Collection: 16.58% Off

Empire Earth 1+2+3: 23.03% Off

Eschalon: Book 1+2: 18.71% Off

Etherlords 1+2: 16.61% Off
Thanks to Fever_Discordia

Fallout 1+2+Tactics: 33.3% Off
Thanks to te_Lanus

Gabriel Knight 1+2+3: 16.58% Off

Guilty Gear Series: 24.96% Off (Includes X2, Isuka)

Hitman 1+2: 18.71% Off

Independence War 1+2: 16.61% Off

Interstate '76+'82, 16.61% Off

Journeyman Project 2+3: 16.61% Off

Kings Quest 1-9: 33.3% off (in 3 collections)

Krondor Series: 16.61% Off (Includes: Return of, Betrayal At)

Lands of Lore 1-3: 16.61% Off (In one set of two, one stand alone)

Legacy of Kain Series: 16.57% Off (Includes Soul Reaver 1+2, Blood Omen 2, Defiance)

Little Big Adventure 1+2: 16.61% Off
Thanks to Fever_Discordia

Leisure Suit Larry Series: 22.67% Off (Features one 6 game collection, two stand alone titles)
Thanks to UndeadCow

Lords of the Realm 1-3: 16.61% Off (One set of two, one stand alone)

Magic Carpet 1+2: 16.61% Off

Master of Orion 1-3: 18.71% (In one set of two, one stand alone)

Moto Racer 1-3: 22.67% Off (In 3 stand alone)

Myst Series: 20.97% Off (Includes Real Myst, Myst Masterpiece, Riven, Uru, Myst 5)

Nations Series: 16.61% (Includes Alien Nations, The Nations Gold Edition)
Thanks to Adambiser

Neverwinter Nights 1+2: 16.64% off

Oddworld Series: 40.87% (Includes Abe's Oddysee, Abe's Exoddus, Stranger's Wrath)
Thanks to te_Lanus

Phantasmagoria 1+2: 18.8% Off

Police Quest 1-4 + Swat 1-2: 24.97% Off (In one set of two, one collection of 4)

Populus 1+2+Beginnings: 16.58% Off

Sam and Max Series: 57.89% Off (in 3 collections of episodic games)

Scream 1+2: 16.61% Off

Serious Sam 1+2: 33.31% Off

Seven Kingdoms 1+2: 16.68% Off

Simon the Sorcerer 1+2+3: 22.15% Off

Space Quest 1-6: 24.97% Off (in two collections)

Spell Force Series: 20% Off (Includes Platinum, Shadow Wars, Dragon Storm)

Star Control 1-3: 16.61% Off (In one two game set, one stand alone)

Still Life 1+2 And Post Mortem: 24.97% Off

Stronhold HD, Stronghold Crusader, and Space Colony: 23.03% Off

Syndicate+Syndicate Wars: 16.61% Off

Syberia 1+2: 24.97% Off

Tex Murphy Series: 30.51% Off (3 stand alone titles, one set of two games)
Thanks to te_Lanus

Thief 1+2+3: 36.64% Off

Tomb Raider Series: 33.3% Off (Includes one collection of 3, one set of two games, one stand alone)
Thanks to te_Lanus

Total Annihilation: Commander + Kingdoms: 16.68% Off

Tropico 3 Gold + Reloaded: 14.25% Off
Thanks to Itchanddino

Two Worlds 1+2: 10% Off

UFO: Aftermath + Aftershock + Afterlight: 23.03% Off

Ultima Series: 16.59% Off (Across 9 individual games and collections)

Unreal Series: 40% Off (Features GOTY, Gold, Tournament 2004, 2)
Thanks to Adambiser

Wing Commander 1-4 + Privateer: 16.57% (Includes 3 stand alone, one set of two)

Worms 2, United, Forts_Under Siege: 16.58% Off

Zork Series: 16.57% Off (Includes: Return to, Anthology (collection), Nemesis, Grand Inquisitor)
Thanks to Itchanddino

LBA & LBA 2

Etherlords and Etherlords 2

1$ off if you for the 2nd if you own the first (16.something %)

Myst games: 20.97% Off (includes all the Myst games, plus Riven and URU).

Simon the Sorcerer games: 22.15% Off.

The problem is that if you own all games in series, they don't show the discount option (if there's one) when you're logged in.

It's interesting that Master of Orion and Blood are included in these bundles. Perhaps that implies GOG's business division has gotten approval from the new rights holders not only to keep them on GOG but also to discount as a bundle.

Yeah, I mentioned that in the first post.

Dah, looks like I need to upgrade my reading skills ;D

Leisure Suit Larry - 22.67% off

No discount for Alan Wake, Might & Magic, Heroes of Might & Magic, or Far Cry 1-2

40% off
Unreal 2: The Awakening SE
Unreal Gold
Unreal Tournament 2004 ECE
Unreal Tournament GOTY

23.03% off
Age of Wonders
Age of Wonders 2: The Wizard\'s Throne
Age of Wonders: Shadow Magic

If you own all the games, you don't see the bundle discount...

Tex Murphy : 30.51% off (since I've got one)

16.61% off
Alien Nations
Nations Gold Edition, The $5.99

Is that all 4 Legacy of Kain titles? Mentioned that in the first post.

Alien nations is on sale too for 16% .


EDIT: Ninja'd

Yes, don't own one here :P

Though you can't see the discount option, if you add all the games of series you own in your cart, you still get the discount.