Pretty much. The Sonic Adventure games are fine for now, though.

i luckly got everything now, mega drive + genesis collection, dreamcast collection, sonic cd + adventure 2 battle

ALL the games from SEGA Mega Drive & Genesis Classics will be delisted (3 Sonic games were delisted in the past).

5 games out of 7 will be delisted from Dreamcast Collection Bundle, Sonic Adventure DX and Sonic Adventure 2 are safe for now, yet I heard conflicting news that those games are to be delisted on consoles in Germany and Italy on 6th on December (some claim that on Steam as well).

https://support.sega.com/hc/en-gb/articles/29776767664145-SEGA-Classics-FAQ#h_01JBWBDWT9PXWHVDPMSZB9EB90

Sega Dreamcast games are also being delisted.

Yes, games like Nights, CT, SBF, SC5 2 and JSR.

Not REZ though ? I wonder if they'll be replaced with newer ports maybe.

What about people already possessing these games in their library? Can Steam remove games from the SEGA Mega Drive & Genesis Classics package ? I heard Rockstar removed musics from games we already own in our library so I was wondering if these de-lising are just for new buyers or are applied to people that paid for these games.

Skytrill の投稿を引用：

What about people already possessing these games in their library?

They can still play them as usual.

Skytrill の投稿を引用：

What about people already possessing these games in their library? Can Steam remove games from the SEGA Mega Drive & Genesis Classics package ? I heard Rockstar removed musics from games we already own in our library so I was wondering if these de-lising are just for new buyers or are applied to people that paid for these games.

Yes the music was removed from GTA games because the music is licensed, So instead of just removing game completely, took them out.

This website has what they claim to be a full list of delisted games[www.mensjournal.com].

Lists and databases generally aren't eligible for copyright protection under U.S. law, likely because they are considered non-expressive and strictly factual and facts are excluded from protection under Title 17 Section 102(b) so I can give the full list of games Sega is removing from Steam here:

• Alex Kidd in the Enchanted Castle
  
• Alien Soldier
  
• Alien Storm
  
• Altered Beast
  
• Beyond Oasis
  
• Bio-Hazard Battle
  
• Bonanza Bros
  
• Columns
  
• Columns 3
  
• Comix Zone
  
• Crack Down
  
• Crazy Taxi
  
• Decap Attack
  
• Dr. Robotnik’s Mean Bean Machine
  
• Dreamcast Collection Bundle
  
• Dynamite Headdy
  
• Ecco Jr.
  
• Ecco the Dolphin
  
• Ecco: The Tides of Time
  
• ESWAT: City Under Siege
  
• Eternal Champions
  
• Fatal Labyrinth
  
• Flicky
  
• Galaxy Force 2
  
• Gain Ground
  
• Golden Axe
  
• Golden Axe 2
  
• Golden Axe 3
  
• Gunstar Heroes
  
• Jet Set Radio
  
• Kid Chameleon
  
• Landstalker: The Treasures of King Nole
  
• Light Crusader
  
• Mega Drive and Genesis Classic Bundle
  
• Monster World
  
• Nights into Dreams
  
• Phantasy Star 2
  
• Phantasy Star 3: Generations of Doom
  
• Phantasy Star 4: The End of the Millennium
  
• Ristar
  
• Sega Genesis Classics
  
• Sega Bass Fishing
  
• Shadow Dancer
  
• Shining Force
  
• Shining Force 2
  
• Shining in the Darkness
  
• Shinobi
  
• Shinobi 3: Return of the Ninja Master
  
• Sonic 3D Blast
  
• Sonic Spinball
  
• Sonic the Fighters
  
• Space Channel 5: Part 2
  
• Space Harrier 2
  
• Streets of Rage
  
• Streets of Rage 2
  
• Streets of Rage 3
  
• Super Thunder Blade
  
• SVC: ToeJam & Earl
  
• Sword of Vermilion
  
• The Revenge of Shinobi
  
• ToeJam & Earl
  
• ToeJam & Earl in Panic on Funkoton
  
• VectorMan
  
• VectorMan 2
  
• Virtua Fighter
  
• Virtua Fighter 2
  
• Wonder Boy in Monster World
  
• Wonder Boy 3: Monster Lair

Those aren't just games from this collection, but I'm not sure what was in the dreamcast collection bundle to let you know if it's just games from both this and that. I don't remember Jet Set Radio being in the dreamcast bundle, although it might've been added since the last time I checked.

Tonepoet の投稿を引用：

This website has what they claim to be a full list of delisted games[www.mensjournal.com].

Lists and databases generally aren't eligible for copyright protection under U.S. law, likely because they are considered non-expressive and strictly factual and facts are excluded from protection under Title 17 Section 102(b) so I can give the full list of games Sega is removing from Steam here:

• Alex Kidd in the Enchanted Castle
  
• Alien Soldier
  
• Alien Storm
  
• Altered Beast
  
• Beyond Oasis
  
• Bio-Hazard Battle
  
• Bonanza Bros
  
• Columns
  
• Columns 3
  
• Comix Zone
  
• Crack Down
  
• Crazy Taxi
  
• Decap Attack
  
• Dr. Robotnik’s Mean Bean Machine
  
• Dreamcast Collection Bundle
  
• Dynamite Headdy
  
• Ecco Jr.
  
• Ecco the Dolphin
  
• Ecco: The Tides of Time
  
• ESWAT: City Under Siege
  
• Eternal Champions
  
• Fatal Labyrinth
  
• Flicky
  
• Galaxy Force 2
  
• Gain Ground
  
• Golden Axe
  
• Golden Axe 2
  
• Golden Axe 3
  
• Gunstar Heroes
  
• Jet Set Radio
  
• Kid Chameleon
  
• Landstalker: The Treasures of King Nole
  
• Light Crusader
  
• Mega Drive and Genesis Classic Bundle
  
• Monster World
  
• Nights into Dreams
  
• Phantasy Star 2
  
• Phantasy Star 3: Generations of Doom
  
• Phantasy Star 4: The End of the Millennium
  
• Ristar
  
• Sega Genesis Classics
  
• Sega Bass Fishing
  
• Shadow Dancer
  
• Shining Force
  
• Shining Force 2
  
• Shining in the Darkness
  
• Shinobi
  
• Shinobi 3: Return of the Ninja Master
  
• Sonic 3D Blast
  
• Sonic Spinball
  
• Sonic the Fighters
  
• Space Channel 5: Part 2
  
• Space Harrier 2
  
• Streets of Rage
  
• Streets of Rage 2
  
• Streets of Rage 3
  
• Super Thunder Blade
  
• SVC: ToeJam & Earl
  
• Sword of Vermilion
  
• The Revenge of Shinobi
  
• ToeJam & Earl
  
• ToeJam & Earl in Panic on Funkoton
  
• VectorMan
  
• VectorMan 2
  
• Virtua Fighter
  
• Virtua Fighter 2
  
• Wonder Boy in Monster World
  
• Wonder Boy 3: Monster Lair

Those aren't just games from this collection, but I'm not sure what was in the dreamcast collection bundle to let you know if it's just games from both this and that. I don't remember Jet Set Radio being in the dreamcast bundle, although it might've been added since the last time I checked.

I got the SEGA Bundle way back on Humble Bundle, the Dreamcast collection key unlocked 4 games:

Sonic Adventure DX (still sold)
Space Channel 5: Part 2 (delisted)
SEGA Bass Fishing (delisted)
Crazy Taxi (delisted)

That tier also had Nights into DREAMS (delisted) and Sonic All-Stars Racing Transformed (still on) as separate keys... Ah, looking at that I missed the $1 bundle with Alpha Protocol (delisted).

Jet Set Radio (delisted) also sometimes included in "SEGA Heritage" bundle, but it was a separate key on Steam... Sonic Adventure 2 DX and Battle DLC are also separate.

Dreamcast collection is just 4 games bundled together under one key activation (they're separate games in store).

Important is that all those aren't roms bundled with emulators like their Mega Drive collection, but actual PC ports, some of them from Gamecube.

Caramel КурскУкраїна の投稿を引用：

Ah, looking at that I missed the $1 bundle with Alpha Protocol (delisted).

Alpha Protocol is not delisted for quite some time, however GOG managed to make an exclusive deal with SEGA to offer the updated version on their store. If you buy the game on Steam there is a slight chance of a free update in a few years.

Caramel КурскУкраїна の投稿を引用：

Dreamcast collection is just 4 games bundled together under one key activation (they're separate games in store).

Dreamcast Collection initial key had 4 games indeed:
Crazy Taxi
SEGA Bass Fishing
Space Channel 5: Part 2
Sonic Adventure DX

Dreamcast Collection bundle on Steam had 7 games, I haven't seen any keys for all 7 games though:
Crazy Taxi
SEGA Bass Fishing
Space Channel 5: Part 2
Sonic Adventure DX (still available)
Sonic Adventure 2 + DLC (still available)
Nights into Dreams
Jet Set Radio