This generation especially, Nintendo reached out quite a bit to 3rd parties... but they're basically all Japanese. Nintendo really needs to step up it's game in western development circles and start offering the same sort of incentives, support and collaborations they do in the home market.
For JP stuff though, Nintendo does more directly with 3rd parties than MS and Sony combined, and they're the only 1st party who allows their own studios to develop games for 3rd parties directly. Just this gen, they've had a TON of tie ups and partnerships for games from 3rd party publishers... this also leaves out PAL region only publishing/distribution deals, of which there are a TON (Trauma Center series, Phoenix Wright series, Harvest Moon series, Naruto series, etc, etc), and there's probably some things I've forgotten...
AQ Interactive
- Nintendo studio (Brownie Brown) co-developed Blue Dragon Plus
Capcom
- co-published/promoted Monster Hunter 3/Tri in western markets
- co-developed Classic Controller Pro (specifically for MH3)
- Chunsoft developed Pokemon Mystery Dungeon series
- published/promoted Tenchu: Dark Secret in western markets
- published/promoted Lonpos in western markets
- Hudson studio (Monegi/CAProduction) developed Mario Party 8/DS
- inclusion of PC Engine/TurboGrafx-16 formats in Virtual Console
- published/promoted Sudoku Gridmaster in western markets
- published/promoted Professor Layton series in western markets
- Nintendo studio (Brownie Brown) developing Fantasy Life, also developed "London Life" for Layton 4
- Nintendo studio (NST) developed Ridge Racer DS
- Nintendo studio (Monolith Soft) developed Super Robot Taisen OG Saga series and DBZ Attack of Saiyans
- Namco Bandai studio (Namco) developed Flash Focus
- published/promoted Glory of Heracles in all markets
- published/promoted Meteos in western markets
- Nintendo studio (Genius Sonority) co-developed Dragon Quest Swords
- Nintendo studio (Intelligent Systems) developed Dragon Quest Wars
- Nintendo studio (Brownie Brown) developed Heroes of Mana
- published/promoted Children of Mana in western markets
- published/promoted Dragon Quest IX in western markets, likely doing the same with Dragon Quest X
- Square Enix studio (SE Osaka) developed Mario Hoops, developing Mario Sports Mix
- Square Enix studio (Taito) developed Takt of Magic
- Mario & Sonic Olympics collaborative project, 2 games and counting
- inclusion of Sega Mark III/Master System and MegaDrive/Genesis formats in Virtual Console
- inclusion of Neo*Geo formats in Virtual Console
- published/promoted Dynasty Warriors DS in western markets
- published/promoted Fatal Frame: Mask of the Lunar Eclipse in JP market
- published/promoted Samurai Warriors 3 in western markets
- Tecmo Koei studio (Team Ninja) co-developing Metroid: Other M
