nihongoknow.com/category/jlpt-grammar/
Archive of JLPT grammar lessons covering levels N5 through N1, explaining grammar structures with practical usage examples and common mistakes.
GrammarJLPT and other testsIn JapaneseJLPT N5JLPT N4JLPT N3JLPT N2JLPT N1ParticlesVerb conjugationCountersJLPTListening practiceTransitive and intransitiveConversationStudy methodsIntermediate