More to explore:
Plural nouns anchor chart
irregular plural nouns
This is a cheap and simple way to practice plurals with students: write the noun on the sentence strip, fold the right hand corner to cover up whatever gets taken away on the reform of the word, then write the new ending that makes the word plural.
plural nouns chart
teaching irregular plurals
Sorting nouns as being singular nouns or plural nouns
plurals from Montessori for Everyone