One could be 'Overlord'. It also has a male protagonist in an isekai setting with a lot of power - much like what the title 'shounen yuusha wa isekai wo gyuujiru' might imply. Another could be 'Konosuba'. It has a young male lead in an isekai world, though the tone is more comical compared to what we might expect from the given title.
There's 'Sword Art Online'. While it's not exactly the same, it has a young hero (sort of) in a virtual world which can be seen as a type of isekai. Also, 'Log Horizon' is a good one. It has a male lead in an isekai - a world that has its own rules and the protagonist has to navigate through it, similar to what might be in 'shounen yuusha wa isekai wo gyuujiru light novel'.
Since I haven't read this light novel specifically, it's hard to give a detailed account. However, based on the words, it seems that the story might revolve around a male protagonist (shounen yuusha). The 'isekai wo gyuujiru' part could suggest that he has some sort of extraordinary ability or mission related to the other world (isekai). Maybe he's on a journey to conquer or understand this new world, which is a common theme in light novels.
Since we don't really know the details of 'shounen yuusha wa isekai wo gyuujiru novel', it's a bit of a stretch to recommend similar ones precisely. However, in the isekai genre, 'Re:Zero − Starting Life in Another World' is well - known. It has a young male protagonist who has to face many difficulties in an isekai world. Also, 'Konosuba: God's Blessing on This Wonderful World!' has comical elements along with the isekai setting which could potentially be somewhat similar depending on what 'shounen yuusha wa isekai wo gyuujiru novel' is really about.
I'm not sure specifically as I haven't read this novel. It might be about a young hero ('shounen yuusha') who is involved in another world ('isekai') in some way related to 'gyuujiru' which might be a special action or concept within the story.
I'm not sure exactly as I haven't read this light novel. But generally, 'isekai' often involves a character being transported to another world. Maybe the'shounin yuusha' (young merchant hero) has some sort of adventure or growth while making their way in this new world of 'isekai' that the novel is set in.
Given the title, the most prominent character should be the shounin yuusha. However, in an isekai story, there are usually other important characters too. There could be a mentor figure who helps the young merchant hero understand the ways of the isekai world. There might also be antagonists, perhaps other merchants who are jealous of his success or local villains in the isekai world who try to stop him from achieving his goals. But again, this is just a guess without having read the actual light novel.
One similar light novel could be 'Overlord'. It also involves an isekai setting where the main character has certain powers and skills. Another is 'Re:Zero − Starting Life in Another World' which has a protagonist who has to use his wits and some special abilities in the isekai world. And 'Sword Art Online' has elements of characters using skills in a virtual world that can be somewhat comparable to an isekai.
One similar light novel could be 'KonoSuba'. It also has elements of isekai with a comical take on the genre. Another might be 'Re:Zero − Starting Life in Another World' which has an interesting take on the isekai concept though not exactly the same as 'isekai wa smartphone totomoni'.
Well, if you like 'fukushuu o koinegau saikyou yuusha wa light novel', you might enjoy 'That Time I Got Reincarnated as a Slime'. It has a unique protagonist and an engaging story. Also, 'Re:Zero − Starting Life in Another World' is quite popular and has elements like a complex main character's journey, similar to what might be expected in the given light novel. 'Grimgar of Fantasy and Ash' is another light novel that has a group of characters in a fantasy setting, which could be somewhat related in terms of genre.
One similar light novel could be 'That Time I Got Reincarnated as a Slime'. It also involves the isekai concept where the main character is transported to a different world and has to face various challenges. Another could be 'Overlord', which has an OP (over - powered) character in an isekai setting. And 'Sword Art Online' has some elements of a different world and adventure, though it's more focused on a virtual reality world which is somewhat different but still has similarities in terms of the adventure and character development aspects.
Yes. One similar light novel is 'That Time I Got Reincarnated as a Slime'. It shares the isekai concept and has an interesting protagonist who adapts to a new world. Also, 'Overlord' is a good recommendation. It has a powerful protagonist in an isekai world, like in 'isekai wa smartphone', but with a different kind of power dynamic and story development.