If given the choice, I’ll often not use a textbook for reasons I explained in this other post: No Textbooks for Me! When I don’t use a textbook, I’ll use the following sites for ESL lesson planning ideas:
1. ESL Writing. The listening lessons are excellent and are great for getting some discussion going on in your classes. The writing stuff is decent too, including practice worksheets on editing, making good sentences, etc.
2. Breaking News English. I use the 2-page “mini-lessons” exclusively because the full lesson plans just have way too much repetition. I’ll often take the article and then use that as the basis for my own lesson plan that I make.
3. Film English. Excellent lesson plans based on short videos. I haven’t really delved fully into this site, but there’s lot of potential.
4. Business English Pod. This is my go-to site for everything English job interviews or business English. They have a paid part of the site, but I’ve been happy with only their free content so far. It’s also a great site for students to study with on their own.
5. ESLSpeaking.org. It’s my site! I use lots of these activities for any of my speaking or conversation classes. You could also check out this book of mine on Amazon: 39 No-Prep/Low-Prep ESL Speaking Activities: For Teenagers and Adults
You’ll have enough lesson planning ideas for months!