Basic Trope: A person from a marginalized group travels back in time and experiences prejudice
Straight: Alice, a black person, travels to a time where slavery is legal and experiences racism.
Exaggerated: Every white person in the past becomes filled with rage at the mere sight of a black person.
Downplayed: People in the past are prejudiced and do feel uncomfortable around Alice, but don't go out and say it because they want to be polite.
Justified: Whenever a character who isn't a white, heterosexual, Christian male travels back in time, (in the U.S. at least) they will likely experience prejudice. So most instances of this trope are arguably justified.
Alice, a black person from the The Roaring Twenties, travels forward in the future, and is quite shocked when she discovers a future (FAR into the future, still not our times) almost devoid of racism and prejudice.
A person travels forward in time and experiences prejudices that don't exist yet (such as eye color or hair color).
A white man travels into the future and finds that now he is the member of the marginalized group... Or in a country and past time period when white people wouldn't be welcome — Sakoku-era Japan, for example.
Zig Zagged: Alice is Ambiguously Brown. Depending on the time period, location and how she's dressed, she faces greater or lesser amounts of prejudice. Sometimes it's her extremely pale colleague Bob who can't fit in.
Averted: Alice travels back in time but no one is racist towards her.
Enforced: "We can't send a black woman into the 1800's without having her experience racism. It wouldn't be realistic!"
Lampshaded: Alice is chased by an angry mob of racists. "Oh, yeah. I'm in The Fifties."
Invoked: Bob, a white time-traveling criminal, is being pursued by Alice, a black time-traveling cop. Bob accuses Alice of being an escaped slave which leads to her capture and his escape.
Exploited: Bob, a white time-traveling criminal, is being pursued by Alice, a black time-traveling cop. Bob escapes while Alice is attacked by a mob of racists.
Alice refuses to go back in time to a period where racism is still dominant.
Only shapeshifters are allowed to use time travel, since they can physically morph to avoid persecution in any time they might wind up in.
Discussed: Alice wants to go back in time, but her associates discourage it because she is black and might experience racism.
Conversed: Two characters are watching a movie. One says "Why would they send Alice back in time? She's black and racism might hinder her work."