I've only seen season 1 of the Netflix show. I'm not familiar with the books or the video game, so my typings are based only on the show. They might change after I watch season 2.

Geralt: ESI or SLI. I could see an argument for either type for him. He's more of a lone wolf, mercenary type of character -- valuing Te/Fi. He's stoic and he doesn't seem to care at all for any sort of collective or emotional expression.
Yennefer: I actually think she's LIE. From what I remember, she expressed a desire to feel special to someone - longing for a close relationship - but struggles with this. This seems more indicative of Fi suggestive. She also cares a lot about power, but more in an individualized way that I think is more consistent with gamma.
Jaskier: EIE/ESE. Geralt and Jaskier have this Shrek and Donkey dynamic going on lol where he annoys Geralt with his Fe but Geralt keeps him around anyways.

Its been awhile since I watched the show, so I don't remember the rest of the characters that well