I think the only comedies from the last 20 years I would consider are Arrested Development and It's Always Sunny in Philadelphia. Maybe Marvelous Mrs. Maisel if that qualifies as a comedy?
Hmm...
In no particular order:
The Wire
Breaking Bad
Rectify (probably the most well written show of all time)
Fargo
Better Call Saul
Honorable mention: Justified, Arrested Development, Six Feet Under, Boardwalk Empire
I feel like I'm totally forgetting something. Also, I can't include a...