Definitely 'The Rising of the Shield Hero'. It stands out with its story of the protagonist being falsely accused and having to rise above the odds in the isekai world. There are a lot of elements like character development and a richly detailed world. Also, 'Log Horizon' is quite good. It focuses on the strategic aspects of living in an isekai world, especially when it comes to the in - game economy and politics.
I'd also recommend 'How a Realist Hero Rebuilt the Kingdom'. In this isekai novel, the main character uses his real - world knowledge to try and rebuild a kingdom in the new world he's been transported to. It's interesting to see how he applies modern concepts to a medieval - like setting.