I’ll list here some of the websites I value as an English teacher:
Academy of American Poets
American Authors
Bartleby
Books and Writers: Authors’ Calendar
Bibliomania
The Poetry of Eli Siegel
Classic Books for College Students
Classic Notes by Grade Saver
Creative Quotations
Etymonline
The Literature Network
Modern & Contemporary American Poetry (UPenn)
Poem Hunter
Purdue University: Online Writing Lab (OWL)
NCTE
NYSEC
New York Public Library
WebEnglishTeacher