Chuck is right about gospel and Savoy.
Some of the biggest sellers in the R&B genre for Savoy were as follows, with rankings within each year from the "Hot Chart" compiled by Big Al Pavlow in his "The R & B Book. A Disc-History of Rhythm & Blues." Based on this information, their biggest sellers in the pop field were likely Johnny Otis, Paul Williams, Varetta Dillard, and Nappy Brown.
1948:
Hal Singer. Cornbread. #9 (#45 on 1943-1949 Top Records)
Paul Williams. Thirty-Five Thirty. #33
Paul Williams. Waxey Maxie. #65
Brownie McGhee. My Fault. #79
Don Byas. September Song. #85
Don Byas. London-Donnie. #87
1949:
Paul Williams. The Huckle-Buck. #1 (#4 on 1943-1949 Top Records)
Big Jay McNeely. The Deacon's Hop. #15. (#81 on 1943-1949 Top Records)
Billy Wright. Blues For My Baby/You Satisfy. #39
X-Rays. I'll Always Be in Love With You. #58
Felix Gross. Love For Christmas. #69
Hal Singer. Beef Stew. #83
Paul Williams. He lKnows How to Hucklebuck/House Rocker. #95
1950:
Johnny Otis. Double Crossing Blues. #2 (#6 on 1950-1954 Top Records; #70 on 1950-1959 Top Records)
Johnny Otis. Mistrustin' Blues/Misery. #8 (#36 on 1950-1954 Top Records, #135 on 1950-1959 Top Records)
Johnny Otis. Cupid's Boogie. #12 (#60 on 1950-1954 Top Records, #193 on 1950-1959 Top Records)
Johnny Otis. Deceivin' Blues. #30 (#131 on 1950-1954 Top Records)
Johnny Otis. Wedding Boogie/Far Away Blues. #36 (#146 on 1950-1954 Top Records)
Johnny Otis. Dreaming' Blues. #73
Johnny Otis. If It's So Baby/If I Didn't Love You So. #97
1951:
Johnny Otis. Rockin' Blues. #12 (#45 on 1950-1954 Top Records, #158 1950-1959 Top Records)
Johnny Otis. Gee Baby/Mambo Boogie. #22 (#95 on 1950-1954 Top Records)
Four Buddies. I Will Wait. #27
Johnny Otis. All Nite Long. #49
Billy Wright. Stacked Deck. #80
Billy Wright. Heh, Little Girl. #89
1952:
Varetta Dillard. Easy Easy Baby. #48
Johnny Otis. Sunset to Dawn. #89
1953:
Varetta Dillard. Mercy, Mr. Percy. #36. (#137 on 1950-1954 Top Records)
Emitt Slay Trio. My Kind of Woman. #62
1955:
Nappy Brown. Don't Be Angry. #10. (#72 on 1955-1959 Top Records)
Varetta Dillard. Johnny Has Gone. #41
Nappy Brown. Pidily Patter Patter. #59
1956:
Big Maybelle. Candy. #74
1957:
Jive Bombers. Bad Boy. #56
Nappy Brown. Little By Little. #72
1958:
Nappy Brown. It Don't Hurt No More. #61