Anime

Konasuba. Since it's a parody of the genre. I've avoided everything else in the genre.

Sword Art Online taught publishers that people really want bland wish-fulfillment stuff where the hero just steamrolls any problems that shows up and then gets all the girls. Of course SAO had other things going for it, like good animation and a great soundtrack, but that isn't what they can easily copy.

Shield Hero taught publishers that people want that but also with the main character owning slaves for some reason.

Anyways, due to these two things isekai has been almost universally weird af lately. That said, it's not all bad. I liked The Eminence in Shadow, but I recommend the manga adaptation over the anime. The mangaka just has a really good sense of comedic timing. I've also heard good things about Shangri-la Frontier. There are a few more good isekai if you look at the pre-SAO era. Vision of Escaflowne was really good, as long as you come in with the expectation that this is a shoujo mech isekai so it'll have a somewhat different feel to it.

Of course, that's if you're stuck on wanting to watch/read isekai. There's been tons of great stuff coming out every year that has nothing to do with isekai. My favorites from the last 5 years have been:

• 2020 - Keep Your Hands Off Eizouken! - A team of high school girls form a club and set out to make whatever anime they can with their limited resources
• 2021 - Vivy -Fluorite Eye's Song- - The first AI-powered humanoid robot tries to prevent the robot apocalypse
• 2022 - Chainsaw Man - A sad boy has a wild (and bad) time. Honorable mentions go to Spy x Family and Bocchi the Rock. It was a strong year.
• 2023 - Skip and Loafer - A book-smart girl from the country moves to Tokyo for a better high school and adapts to city life
• 2024 - LOOK BACK - A story about 2 artists. Honestly this year was stacked too, so honorable mentions go to Bang Brave Bang Bravern! (big gay robots), DAN DA DAN (romance, yokai, and aliens), and Delicious in Dungeon/Dungeon Meshi (traditional fantasy, but really well executed).

Notably even though every year a whole pile of isekai gets released not one of them made it into that list. I'd avoid them as a general rule for a while, except when you hear a lot of people recommending a specific specimen.

Zenshu is killing it this season. Anime-original story, tries to actually connect with Natsuko Hirose's "real life" (not just focused on the fantasy world but also her experiences before getting Isekai'd), etc. etc.

Reincarnated as a Slime is my favorite somewhat trashy isekai (as in: it follows all the tropes but otherwise the animation quality is actually really good). Its an "overpowered" show where the main character rarely comes across a real challenge though.

I'm a Spider, so What?! is a fun boss rush that had a deeper than expected story. Main character always wins of course, lol, but I think it "felt" like a challenge as she learned combat of this new world?

Overlord is a "take over the world" / "Kingdom builder" (Slime also is a kingdom builder but its not as good as Overlord). Overpowered once again, literally no one in the new world can challenge the main character. But I don't think that's a bad thing for Overlord, it allows the plot to focus on kingdom building / alliances / kingdoms rather than the fights.

A grossly underrated Isekai is: "The Weakest Tamer Began a Journey to Pick Up Trash". Its basically just this young girl talking to herself for ~12 episodes as she's forced to run away from home. https://www.youtube.com/watch?v=-biFNoRk-3I . Still, the people she meets on the journey are all helpful and optimistic. This isn't a battle anime (she runs away from pretty much every fight), and she very much relies upon the kindness of strangers. Its actually quite unique for an anime since she doesn't have nearly as much "Because I'm the Main Character" energy, even if she gets a few special friends along the way. Very much an "underpowered" main character, who has to mostly dig through trash, cry, find friends and run away constantly.

Re:Zero and Jobless Reincarnation are probably the most popular Isekai. But I didn't like them. I figure I should mention them though.

Since I didn't see it here:

• Saga of Tanya the Evil | A psychopathic atheist bureaucrat makes a deal with God that he'll keep his beliefs no matter what. So God reincarnates him (now her, named Tanya) into an alternate universe where it's WW1, but some people are born with magic. The main character is one of those people, and essentially has a crazy amount of magic, but can only use it if they pray to God. Tanya decides to double down on their beliefs that God doesn't exist and plans on outlasting the war.

I think parodies and deconstructions of the isekai genre are fun:

• Villainess Level 99
• The Hero is Overpowered but Overly Cautious
• My Instant Death Ability Is So Overpowered

I haven't seen anyone mention Isekai Nonbiri Nouka. I thought it was pretty good.

There’s a ton of well-reviewed isekai out there. But there’s also a lot of really bad stuff too.

There are good isekai, but it's littered with slop. Some I enjoyed:

1. Re:Zero
2. Konosuba
3. Ascendance of a Bookworm
4. My Next Life As A Villainess: All Routes Lead To Doom
5. No Game No Life (though note that it's been a looong time since I've seen that one..)
6. Youjo Senki
7. Overlord
8. Re:Creators (mostly interesting because it's a reverse isekai, but has lots of boring exposition)

I think the Chronicles of Narnia is probably the best isekai.

I kinda find modern isekai are very formulaic. If you just want some fan service and an OP power fantasy protag who doesn't struggle at anything, then they look nice enough, but are still kinda trash.

I'd recommend watching some of the early ones when the genre wasn't so well defined:

• Now and Then, Here and There
• Twelve Kingdoms
• El Hazard
• Vision of Edcaflowne

I haven't watched them, but I've heard little but good about Twelve Kingdoms, Magic Knights Rayearth, and El-Hazard.

Re:Zero, Bookworm, KonoSuba, Slime... There are a lot of good isekai out there.

"Good" is subjective. What's your criteria for good?

KonoSuba is a satire/deconstruction of the isekai genre, and it's been well-received.