Chris Mars, drummer for The Replacements, later released several solo albums (on which he sang and played most of the instruments).
Fred LeBlanc of Cowboy Mouth. A great singer with the kit up front.
Pete Rivera of Rare Earth. Pretty distinctive voice, too.
Neko Case played drums in Cub before becoming a solo artist (singer/guitarist) and also singing in the New Pornographers.
I believe Stevie Wonder played the drums on many, if not most, of his studio recordings in the 70’s.
I’m not a Band aficionado, but if one of them was to be considered the primary singer, wouldn’t it be Richard Manuel?
Also, Grant Hart of Husker Du sang lead on his 49% of the group’s songs.
Speaking for us “non-famous” drummers who also sing, the last band I played for allowed me to sing lead on the old Stones cover “It’s All Over Now” (we did the Molly Hatchett version, which is more of a “talkin” tune, so I was able to carry it off pretty well.)
However , when it came time for harmonizing, our sound man very wisely turned my mic off, so I looked like I was singing, but didn’t conflct with the voices singing lead.

Thanks
Q
He did sing lead on one Nirvana song I’m aware of - a B-side called “Marigold.” Speaking of which, Kurt Cobain was a former drummer (as was Chris Cornell of Soundgarden, and probably plenty of other singers I don’t know about).
The drummer from Grand Funk sang We’re an American Band…
Andy Sturmer sang for Jellyfish
Jim Capaldi sang some of of Traffic’s songs, IIRC
**Tim O’Reagan ** of The Jayhawks
The Band had three lead singers: Helm, Manuel, and Rick Danko.
Helm was lead singer on “The Weight” (with Danko), “The Night They Drove Old Dixie Down,” “Up on Cripple Creek,” and “Rag Mama Rag.”
Manuel did “Tears of Rage,” “Chest Fever,” “I Shall Be Released,” “King Harvest (Has Surely Come)” and “The Shape I’m In.”
Danko did “Stage Fright,” among others.
No one was really primary, though the three best-known songs all had Helm as lead.
One more: Graeme Edge of the Moody Blues occasionally did vocals.