>>44341960I think the first isekai anime to seriously embrace the computer game aesthetic was "Hack-Sign" but "Sword Art Online" was what really made isekai a popular staple of modern anime culture.
In Monster Rancher, the isekai part is just an excuse for the plot premise of "boy from earth travels unknown world". Iirc it's not even that prominent in the show itself. I really think that the Monster Rancher animation would have been more memorable if the boy protagonist had been like 5 years or so older(roughly matching the MC up with the chick character in terms of age and leading to potential romance teases) and acted more like Gray from Fairy Tail and a bit of edginess wouldn't hurt if the show wanted to set itself apart as it's own thing(just like YuGioH was a bit on the darker side). The anime being the way it is it comes of as some weird AU Pokemon/Digimon fanfictionesque story with little originality in terms of meta tropes to set it apart from those shows. It just doesn't really stand out on its own. It lacked a strong identity, unlike something like Bakugan(Bakugan did the whole Internet thing way better than Digimon in my opinion).