The Expanse seemed to be pretty even throughout its six season run. Maybe the only real "ding" is the fourth season where most of Jame's crew is on a planet.

Firefly. I'm not sure if there was enough gas in that show's tank to have kept it on this list or if the plug getting pulled at 14 episodes did it a favor for us fan's collective opinion of it.

Though I'd imagine that "space opera" is easier to keep the story/plot quality pretty even as writers can always just switch to a different set of characters to avoid having to deal with writing their way out of plot corners.

Fleabag

Sad horse show

Barry

Review

Black Sails

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.

Fullmetal Alchemist: Brotherhood (haven't watched 2003), remember that being rather consistently good

Dirk Gently’s Holistic Detective Agency. It’s perfect from start to finish, but it ended after the 2nd season because it was cancelled 💀 so might not count.

Lost. That season 3 finale was perfect.

Sopranos for sure. I think Deadwood would count here as well

the leftovers. rly good shit.

Dark. I love Twin Peaks equally but season 2 has a serious drop off in the middle.

The Wire. Yes, the final season is still great, you plebs.

Santa Clarita Diet. I will never forgive Netflix for cancelling that show.

I thought The Wire was basically perfect all the way through, though a lot of people didn’t like the final season so much

Scavengers Reign is an exceptional work of art that I think not enough people have seen! I can't recommend it enough

Edit: also, The Terror is another show that very few people seem to have watched, and it's unbelievably good. It was supposed to be just a limited series, but they tacked on a second season and tried to turn it into an anthology show. Ignore that aspect, think of it as a miniseries and it's one of the best horror shows I've ever seen.

Venture bros, conversely it wasn't dragged out long enough

Steven Universe

Avatar

Bojack Horseman

Venture Bros.

Party Down

Silicon Valley

Star Trek TOS, TNG and DS9 are inconsistent, but trend toward better.

Community is often derided for a falloff in quality halfway through, but I actually think it's quite funny all the way

Scrubs if you stop at it's intended series finale episode. The studio execs forced them to keep going with a cast change, but you can just stop watching at that point.

Joe Pera Talks With You is an amazing show. The first season is probably the strongest season, but that's more of "This is too perfect to be improved" rather than a quality drop off. It's Adult Swim's most genuine and heartfelt show by a long mile. It's the cure for irony poisoning and insomnia. I think this show could have ran a lot longer than it did, but the finale of season 3 serves as a solid ending for Joe and Sarah.

Life & Times of Tim stays pretty fucking funny the whole time, and even improves as the show goes on. Voice acting is really good.

I'd say Death Note stays pretty consistent, definitely one of my favorite animes

Farscape. It just got better as it went along.

The Venture Brothers, probably one of the only show I know that gets significantly better as the seasons go on.

Some I have not seen mentioned here are Hanna, Counterpart, and The Outer Range

I liked the parasyte anime. The only drop off is

The Great.

Might be the best show i've seen in a long time, and solid from beginning to end.

The Americans was really good. I've been working my way through Babylon Berlin which has been very good so far.

Mr Robot

Pantheon

I think Stranger Things S1 is pretty good. After S1, you can stop at any time you're no longer feeling it and not be missing out on anything.

I, Claudius is perfect television from start to finish but I dunno if it counts since it was a major production with a bunch of the best actors of all time in it.