Some nice, smooth, consistent quality. Better Call Saul was in my opinion pretty consistent. Single season anime is almost always consistent, like My Dress-Up Darling or Terror in Resonance.
Not dragging on longer than the series needs to seems to be a key point.
I thought She-Ra and the Princesses of Power stayed good right through the end.
Almost every episode of TNG is good, and the few bad ones were concentrated toward the beginning, not the end.
I answered Stargate as an overall TV franchise to the opposite question earlier, but SG-1 and Atlantis taken as individual series both stay good, although SG-1 is basically a different also good series in its last three seasons.
Tengen Toppa Gurren Lagann rules all the way through, before and after the timeskip.