People try to spin it, but Kanye has possibly done more leeching than Jay:
T-Pain- featured on "Good Life" back when everybody had a T-Pain feature
Timbaland- got him to do additional drum work on "Stronger" and "Good Life" based on how "The Way I Are" sounded in the club next to the original "Stronger". He even admitted that Graduation wouldn't sound like it sounded had it not been for Futuresex/Lovesounds
Autotune- Wayne raps in autotune, next Kanye starts droppin' verses in autotune and even made a full album using it with 808's & Heartbreak
Lex Luger- In 2010, Luger was the go-to for the trap sound. Kanye gets him to co-produce "See Me Now" and the initial lead single for Watch The Throne, "HAM"
Daft Punk- In 2013, Daft Punk made a huge comeback and possibly their biggest commercial success over here. Next thing you know, they are co-producing several songs on Yeezus. I know Kanye sampled them on "Stronger" and people front like he helped introduce them or he was the first to do it. Busta's "Touch It" was huge in 2006 and it also sampled Daft Punk
That's not to take anything away from Kanye, but if we're calling out artists for being leeches, he's also guilty of it.