Artists who haven't done netorare (or the like)

False.
There are so many fun ways for an NTR to happen.

Example A: Johnny Maincharacter is finally about to have sex with Susan Girlfriend, he removes his pants revealing his tiny pecker, to which Susan Girlfriend laughs, then brings in her friend Jamal Niggadick to demonstrate to Johnny Maincharacter what a real cock is- and how to use it. Thoroughly. Much to Johnny Maincharacter's dismay.

Example B: Johnny Maincharacter is on a date with Susan Girlfriend, they're walking down the street when suddenly Jamal Niggadick and his gang of hooligans jumps out of a nearby allyway and drags them both in. Johnny Maincharacter is tied up and helpless, as Jamal Niggadick and his gang furiously rape Susan Girlfriend. She hates it at first but soon begins to love the superior large cock of Jamal and his gang.

Example C (The reverse-NTR): Johnny Maincharacter is too much of a wussy to fuck Susan Girlfriend. One day, Johnny Maincharacter and Susan Girlfriend are on a double-date with their respective best friends, Jim Everyman and Donna Stupidbitch.
Susan complains that Johnny never fucks her, to which Jim and Donna get saucy and start to get it on. Susan Girlfriend, starved for sex, looks on with lustful eyes. Jim makes a move on her and starts rubbing his dick against her, to which Johnny Maincharacter decides he doesn't like whats going on. He reveals his MAMMOTH penis, fucks the shit out of Susan Girlfriend, AND Donna Stupidbitch, effectively NTR'ing Jim Everyman.

Shall I go on?

Example B is what typical NTR happen
Example C is called reserve-NTR yourself which is not NTR. We dont call reserve-rape rape, we call it lucky bastard.