Franky
Shogun Franky becomes more streamlined, think Isaac from World Seeker
Franky upgrades his suit to incorporate Seastone into his fists
Unlocks Armament Haki
Nami
Zeus Climatact infused with Seastone
Flight (By riding on Zeus)
Unlocks Observation Haki
Is able to create a thunderstorm over a country (Ultimate Move)
Nico Robin
Flight through Wings
Unlocks Armament Haki
Unlocks Awakening of her devil fruit thus making her able to create physical copies of everything she touches.
Chopper
Accessing the Monster Point without a rumble ball
Improves endurance
Unlocks Armament Haki
Brook
New Sword (A Meito- Personally I think he should get one of the 21 O Wazamono Swords)
Greater Ice Generation
Full Body Armament Haki (like Pica and Vergo)
Unlocks Awakening of his devil fruit, allowing him to manipulate souls of everything he touches.
Jinbe
Unlocks Advanced Armament Haki
Gains some dope ocean related powers.
*Theory by stealth_hawk