GAMES KEYS

⚠️ Region lock ⚠️
The screenshots are from a USA purchase.

Mad Max: https://i.imgur.com/uaZLKiV.png

RU/CIS: ?
CN: probably {sub/74486}
LATAM: {sub/74485} - compared to other regions, it's just the base game, there are no DLCs included (confirmed)
Germany receives a ROW key {sub/78524} (store sub) that can be redeemed everywhere apart from Japan, but which contains one extra DLC (Mad Max - The Ripper) compared to the package that everyone else receives.
Everyone else - before restock: {sub/74483} - can be redeemed everywhere apart from Japan (confirmed)
Everyone else - after restock: {sub/78524} (includes Mad Max - The Ripper) - can be redeemed everywhere apart from Japan (confirmed)
Mortal Kombat XL: https://i.imgur.com/RY4GbrS.png

Germany, Japan (confirmed), Korea don't receive the game. For Japan, this is replaced with Injustice: Gods Among Us Ultimate Edition, while for Germany there seems to be no replacement even though the price is the same as for everyone else.
RU/CIS: probably {sub/221409}
CN: a region locked key redeemable only in CN, not indexed yet on SteamDB
LATAM: a region locked key redeemable only in LATAM, not indexed yet on SteamDB (source)
Everyone else: {sub/128345} - can be redeemed everywhere apart from Germany, Japan, Korea (confirmed)
Update: Germany also receives {sub/128345} which can now be activated in Germany as the activation restriction was lifted on 2 Nov 2023
Middle-earth: Shadow of Mordor Game of the Year Edition: https://i.imgur.com/B5fRqOO.png

Japan doesn't receive the game. (confirmed)
RU/CIS: probably {sub/221407}
LATAM + India: {sub/221633} (confirmed)
Everyone else: probably {sub/51209} - can be redeemed everywhere apart from Japan
Mortal Kombat 11: https://i.imgur.com/mMFihv9.png

Indonesia, Japan (confirmed), Ukraine, Korea don't receive the game.
RU/CIS + Turkey: probably {sub/328777}
LATAM + India: probably {sub/328776}
Everyone else: {sub/320588} - can be redeemed everywhere apart from Indonesia, Japan, Ukraine, Korea
MK11: Ultimate Add On: https://i.imgur.com/JsktXQp.png

Indonesia, Japan (confirmed), Ukraine, Korea don't receive the game.
Everyone else: {sub/518192} which can be redeemed everywhere apart from Indonesia, Japan, Ukraine. (confirmed)
Batman: Arkham Knight Premium: https://i.imgur.com/19qUcQr.png

RU/CIS: probably {sub/85509}
CN: probably {sub/85511}
LATAM: {sub/85510} (confirmed)
Everyone else: {sub/85500} - can be redeemed everywhere
Injustice 2 Legendary: https://i.imgur.com/X8ASt17.png

Japan doesn't receive the game. (confirmed) doesn't receive the game.
RU/CIS: probably {sub/249065}
LATAM + India: {sub/249066} - can be redeemed everywhere apart from Japan (confirmed)
Everyone else: {sub/249064} - can be redeemed everywhere apart from Japan (confirmed)
Batman: Arkham Origins: https://i.imgur.com/GFqb5AC.png

RU/CIS: probably {sub/33557}
Everyone else: {sub/30275} - can be redeemed everywhere (including RU/CIS) (confirmed)
Back 4 Blood - https://i.imgur.com/0SqM7Uf.png

EU: {sub/638757} - can be redeemed only in European countries (confirmed)
RU/CIS without Russia, Belarus: ?
Asia + Oceania: {sub/638759} (confirmed)
North America: {sub/638756} - can be redeemed only in American Samoa, Antarctica, Canada, Guam, Northern Mariana Islands, Puerto Rico, United States of America, U.S. Virgin Islands (confirmed)
ME / Africa: probably {sub/638758}
LATAM: probably {sub/633804}
China: probably {sub/633803}
The rest of the games do not have region locks (can be redeemed everywhere):
Batman: Arkham City - Game of the Year Edition {sub/14683}
Batman: Arkham Asylum Game of the Year Edition {sub/15606}
Middle-Earth: Shadow of War Definitive Edition {sub/281112}
Gotham Knights {sub/527688}

Regional restriction information obtained through STEAM GIFTS, information posted by user (sensualshakti)
https://www.steamgifts.com/discussion/DbFqg/humble-bundle-wb-100-play-the-legends-all-back-in-stock-claim-asap