“They just don’t make them like they used to” is the type of cliché to earn audible eyerolls, but when it comes to rap and R&B duets, the sentiment is not just trite nostalgia. In the first decade of the millennium, artists like Ja Rule, Fabolous, Jay-Z, and others turned collaborations with R&B stars into Billboard Hot 100 mainstays. These songs were different in their tonal makeup from later pairings of this kind, with a level of unabashed romance that feels like the opposite of the more nihilistic, post-Weeknd sounds that have helped define the most popular hip-hop and R&B songs of the 2010s and 2020s. The tracks here are love songs unafraid of tenderness, celebrations of being engrossed in affection.