Here are some free resources on the Internet which can be extensively used for English training especially the basic, intermediate levels.
1. dictionary.reference.com: = everything Vocabulary! Not just a great site to get complete information (part of speech, meaning, pronunciation, sample sentence, origin & related forms) about the word you searched, it is also a superb resource to explore new words each day. Check their theme based slideshows & activities to make English Vocabulary interesting for students. The mobile app proves to be very handy for quick reference. I am also a big fan of one of its tabs – thesaurus.com which arranges the synonyms, antonyms of the query in alphabetical order & let’s you filter synonyms, antonyms as per complexity or length.
2. en.islcollective.com: Sign up on this site & you can download free worksheets as well as upload & share your worksheets with others. The best thing is that you can search from about 40,000+ worksheets with filters based on grammar topic, vocabulary theme, language functions, student level & student type. A single worksheet can be utilized in a variety of ways depending on how creatively the trainer can think!
3. eyercize.com/practice/paste_read: Helpful resource for increasing reading speed & concentration of the students. Fluency in reading contributes to fluency in speaking, so I would highly recommend this resource for all levels. You can use the text you want your students to read by clicking on ‘New’ button & pasting it in the box.
4. readprint.com: Online library of books, poems & short stories which can be used for discussions & assignments.
5. audioenglish.org: Audios for listening practice with transcripts. The audios are in American or British accents which might be a problem for Indian students but gradually, students generally get comfortable with the accents.
I think, these resources will effectively supplement the English training modules designed by the trainer. Fellow trainers are welcome to share their resources in the comments section!