I’ve seen Star Wars: The Rise of the Skywalker today. Here is a list of the references to the Prequel Trilogy. SPOILER ALERT!
• When Palpatine is threatened by Kylo Ren, he says “I’ve died before” and repeats word for word his line from Revenge of the Sith: “The dark side of the Force is a pathway to many abilities some consider to be unnatural.”
• Many past Jedi communicate with Rey during her fight against Palpatine. Hayden Christensen plays Anakin Skywalker. Anakin tells Rey to bring balance to the Force as he had done before.
Here are the other Prequel Trilogy actors in this scene. Ewan McGregor plays Obi-Wan Kenobi, Liam Neeson plays Qui-Gon Jinn, Frank Oz plays Yoda, and Samuel L. Jackson plays Mace Windu.
There are also some Jedi from the Prequels who are voiced by The Clone Wars actors. Olivia D’Abo plays Luminara Unduli, Jennifer Hale plays Aayla Secura and Angelique Perrin plays Adi Gallia.
(I would note also that Ashley Eckstein plays Ahsoka Tano, although Ahsoka isn’t technically a Prequel Trilogy character)
These are just vocal cameos. No Jedi appear as a Force ghost in this scene.
• There’s a B1 Battle Droid in Babu Frik’s droid shop (it was in the trailer).
• When Poe Dameron and Zorri Bliss talk alone, the music uses a theme from “Return to Tatooine” in the soundtrack of Attack of the Clones.
• When Finn and Jannah talk about their past, the music uses a theme from “Talk of Podracing” in the soundtrack of The Phantom Menace.
• The words “Sith” and “Palpatine” are frequently used, as in the Prequels.
This is it. I hope I’m not forgetting anything. If so, don’t hesitate to tell me in the comments.