Snoop is definitely one of them. But after tons of smoke & getting older it isn't as smooth sounding and haven't been since at least 2001/02.
But outside of that; Biggie had a dope voice, DMX, Jada, Meth, Ja Rule, Sticky, Rock (Heltah Skeltah), Xzibit, Eazy-E, Bizzy Bone etc have dope voices IMO.
Then you had guys like Prodigy who up to HNIC had it, but then after his health, age, drinking etc i doesn't sound the same.
I disagree about 2pac. I feel 2pac's strenght was in his delivery, not his voice. Same with Ghostface, Chuck D, Ice Cube & Scarface too.
Some may disagree but at one point one of The Game's strenght was his voice. That's what made him stand-out a bit more. But after the lifestyle,
age & him trying to sound like every rapper he lost it. He almost always tried to sound like other artists but the voice he had just before Documentary to about 2006 (pre-Doctors Advocate,
too much Dre sounding).