For younger students:

Songs: https://supersimple.com/super-simple-songs/

Flashcards: https://www.mes-english.com/flashcards.php

For older students:

500 Real English phrases

100 common words and antonyms

The Longman Communication 3000 –  a list of the 3000 most frequent words in both spoken and written English

Most Common Prefixes and Suffixes – Scholastic

English corpora https://www.english-corpora.org/

English-Chinese bilingual video on how to use the corpus below: