Core Keeper

Core Keeper

RU/CIS: probably {sub/642306}
CN: {sub/642307} (confirmed)
LATAM without MX: probably {sub/642308}
small SEA: {sub/642309} (confirmed)
IN+TR: probably {sub/642311}
ME+ZA: a region locked key, not indexed yet
Everyone else (including MX): {sub/642312} - a "Tier 1" countries sub that cannot be activated in RU/CIS, SEA, LATAM, TR (confirmed)

Im from mexico so
Everyone else (including MX): {sub/642312} - a "Tier 1" countries sub that cannot be activated in RU/CIS, SEA, LATAM, TR (confirmed)
https://steamdb.info/sub/642312/

Based on the grey market price, I could exchange it for 3 games from this list.

Lugaru HD
Shovel Knight: King of Cards
Gourdlets
Horse Tales: Emerald Valley Ranch
Voltage High Society

Staxel or The Lord Of The Rings: Adventure Card Game - Definitive Edition?

No, but thanks for the offer. I already have those games.