Nelly

Examples of Singing: "Dilemma," "Country Grammar," "Just A Dream"

Nelly was singing on his first single, "Country Grammar," did the same on other massive singles like "Dilemma," and has always been a poster child for MCs who aren't afraid to switch up their style.

Conclusion: Rappers have been fiddling with melody since the beginning, but Nelly played a massive role in really putting the harmonious side of hip-hop on display for crossover audiences.