Producing high-quality language learning materials requires immense effort. By purchasing the official book, you support the publisher (Sanshusha) and ensure they continue to produce resources for future levels (like N1).
Focuses on mastery of approximately 110 grammar points with detailed explanations and practice exercises. Digital versions are often shared via Google Drive Vocabulary (Goi): mimi kara oboeru n2 pdf
If you cannot find (or don't want to risk) a shady PDF, here are three legal and often better alternatives: mimi kara oboeru n2 pdf