A: Cards (Actions) that end your turn immediately if you play them:

Brain Transference: Star Fluxx
Clean Cup!: Wonderland Fluxx
Time Portal: Star Fluxx, Doctor Who Fluxx, TNG Fluxx, Voyager Fluxx,
What Do You Want?: Star Fluxx, Oz Fluxx, Doctor Who Fluxx
I’ll Be In My Bunk: Firefly Fluxx
I’ll Be Right Back: Fluxx Remixx
(These last two cards don’t specifically say that your turn ends immediately, but you certainly can’t continue your turn if you “Excuse yourself from the game and leave the room for a few minutes.”)

Cards (Rules) that end your turn immediately if you choose to utilize their ability:

Swap Plays for Draws
Get On With it

Since Rule-based Free Actions are optional, however, simply putting them into play does not end the player’s turn immediately.