I collected over 12 lists of the Best TV Shows 2021 from the Internet, magazines and newspapers and combined them into one meta-list.  Here are the results: all the shows (including long-running series and miniseries) on three or more of the original source lists, organized by rank (that is, with the TV shows on the most lists at the top).

On 12 lists
Succession (HBO)
The White Lotus (HBO)
Hacks (HBO Max)

On 11 lists
The Underground Railroad (Amazon Prime)

On 10 lists
Reservation Dogs (FX on Hulu)

On 8 lists
WandaVision (Disney+)
Mare of Easttown (HBO)
Only Murders in the Building (Hulu)

On 7 lists
We Are Lady Parts (Peacock)
Squid Game (Netflix)
It’s a Sin (HBO Max)

On 6 lists
Ted Lasso (Apple TV+)

On 5 lists
What We Do in the Shadows (FX)
The Great (Hulu)
Maid (Netflix)
Station Eleven (HBO Max)

On 4 lists
PEN15 (Hulu)
Sex Education (Netflix)
The Other Two (HBO Max)

On 3 lists
Philly D.A. (PBS)
Love Life (HBO Max)
Yellowjackets (Showtime)
Insecure (HBO)
Bo Burnham: Inside (Netflix)
Dickinson (Apple TV+)