There's a lot of mention of Sword Art Online being the anime that made Isekai but back in the 90s it was a mostly Shojo Genre.
How far back does it go?
Rumiko Takahashi in 1985 released a short anime called Fire Tripper in which a girl is gas exploded back to feudal Japan, alot of elements were later reused for InuYasha, more on that later. Any anime adaption of Alice in Wonderland and Wizard of Oz counts as well.
What are the Main Anime?
Four big names of yester year spring to mind, Vision of Escaflowne, Fushigi Yuugi the Mysterious Play, Magic Knight Rayearth and Inuyasha, all four feature a female heroine drawn into another world either through dimensions, a magical book, summoned by a preist or dragged backwards through time respectively.
How does Digimon fit into the equation?
Digimon by definition is also an Isekai by the fact that a group of 7-8 kids get sent to the Digital World but has more roots in the monster trend alongside another well known title, Monster Rancher.
Staying on topic how good are these four female led Isekai?
Escaflowne has argubly the most beautiful score ever composed for an anime.
Fushigi Yuugi was instrumental in establishing the Josei genre.
Magic Knight Rayearth put the artist team of CLAMP on the map as one of their best work.
InuYasha is yet another stellar work by Rumiko Takahashi and her best selling series by far.
What went wrong?
Escaflowne had a botched dub release and is widely forgotten next to stable mates Cowboy Bebop and Outlaw Star, not to mention the plot made no sense and the manga is infinitely different.
The others out stayed their welcome, Rayearth had a dreadful 2nd season, Fushigi Yuugi has not aged well and has been out of the spotlight for two decades now, InuYasha kept going and going and became the punching bag in the awkward era of the 00s where anime was struggling with a hangover, it's also aged the worst of the four shows.
As for Digimon, each season was getting less and less returns until they decided on Digimon Tri and a season 1 reboot.
Did Sword Art Online save Isekai?
Kind of, it's premise added elements that weren't available in 90s Isekai and took inspiration from harem, shonen and even thriller in some cases, Sword Art Online also took inspiration from Dot Hack Sign.
Now we can't get rid of Isekai
Blame covid, Japan's abysmal birth rate and Sword Art Online outstaying it's welcome, on the bright side, female led Isekai made a return with Saints Magic is Omnipotent and to a lesser extent Bofuri, we also have enough try hards to keep anime interesting and it's not devoid of having it's formula mixed in ever more dangerous ways, it's not like the tail end of the early 2000s where anime actually stagnated.
Whether you like it or not, time is a constant and things change as does taste and needless to say these characters haven't aged well.
There's no set order either.
1. Gourry Gabriev from Slayers
Slayers is a fantastic series of very capable characters, pity Gourry isn't one of them, the sheer gap between Lina Inverse and Gourry in power and abilities make for grim reading for the blonde swordsman, not helping his case is trying to be chivalrous to a character that doesn't need help and spending way too much time being the butt monkey.
2. Chang Wufei from Gundam Wing
I was surprised how well Gundam Wing aged but then lose it when you see how much of a misogynist Chang Wufei is, while the franchise isn't short on dramatic fighting types and you can make a decent case for the G Gundam cast to appear on this list also, at least G Gundam wasn't belittling the female characters it did have.
3. Louise Françoise le Blanc de la Vallière from Familiar of Zero
Flaunts her title as an excuse to abuse the lead character, need I say more.
4. Kagome Igarashi from Inuyasha
You could make a case for Akane Tendo but some of her tsundere outbursts are justified considering the company she's around, Kagome doesn't have that excuse, at first Inuyasha did need keeping on a leash but when Kagome practically abuses it for the whole run of Inuyasha it doesn't leave me with much to like.
5. Naru Narusegawa from Love Hina
Get used to the tsunderes, they're usually my first target for these lists.
Naru after a while was really only abusing Keitaro to hide her own insecurities, it's hard to watch at times.
6. Lynn Minmay from Macross
She is literally just eye candy and every sci-fi idol has surpassed her even within her own franchise.
7. Belldandy from Ah My Goddess
Has all the personality of a domestic doormat and easily one of the most beautiful female characters of her era, yet I hate every story that focuses on her.
8. Ryo Saeba from City Hunter
Bad ass or not, you can't get away with Johnny Bravo womanizer behaviour even in anime, Ryo is a frustrating character to watch at times.
9. Haruhi Suzumiya from Melancholy of Haruhi Suzumiya
I haven't really forgiven her for some of the worst aspects of anime fandom, that will require it's own list in the future.
10. Hilary Tachibana from Beyblade
It's thanks to Hilary that Beyblade never really evolved beyond a boys club. It basically boils down to toy anime not being very inclusive, something that hasn't changed much even today.
I think we need to revisit a long forgotten feature on the Fantasy Zone, Genre Savvy, our first subject will be isekai.
Isekai translates as simply going to another world, it's origins are routed in the high fantasy genre with early adopters of Isekai include Rayearth, Fushigi Yuugi and Inuyasha to name a few, other variations of Isekai can also include being stuck in a video game, with Dot Hack experimenting with the concept and Sword Art Online taking it to it's logical extreme, it's popularity exploded in the late 2010s early 2020s helped by the global pandemic but it's over saturation of anime is causing it to die off as ideas run out of steam.
Depending on what you watch can also set the tone, there are lots of examples of the chosen one and fish out of water plots as well as world breakers when the isekai'd character has something that can break the laws of the world they've entered.
The earliest isekai I can name is the Inuyasha prototype Fire Tripper by Rumiko Takahashi.
The future of the genre is a bit up in the air as the next trend, I dub, the best girl anime in which the anime is defined by it's best girl, is taking over the trends boosted by Twitter's outrage over it working against them.