Grammarly
Grammarly Blog: Plural Nouns
An explanation with examples of plural nouns and the spelling rules involved in pluralizing a noun.
Other
Reading From Scratch: Spelling Rules
The "Reading from Scratch" site provides a list of spelling rules with examples.
BBC
Bbc: Skillswise: Plurals and Spelling Rules
The rules for spelling plural words and using them properly in English are made fun and easy with this BBC Skillswise worksheet for students.
Fact Monster
Fact Monster: Spelling Plural Nouns
A chart that shows general rules for regular and irregular plural formations for nouns, plus a list of some exceptions.
Grammarly
Grammarly Blog: Spelling Plurals With S or Es or Other Plurals
Spelling rules and examples for adding -s or -es to make the plural form of a word.
Patsy Stevens
Garden of Praise: Musical Spelling Rules
Use these clever songs to help students learn basic spelling rules. Sheet music, as well as audio files, are available for each of 4 songs. Scroll down the page for interactive practice activity.
ClassFlow
Class Flow: Plurals
[Free Registration/Login Required] Investigate, collect and classify spelling patterns in pluralization; construct rules for regular spellings.
Other
Speakspeak: Spelling: Changing Y to Ies, Ied, Ier
A few rules and examples help students understand when and how to change words which end in -y, for plural nouns, verb forms, adjective and adverb forms.