SpellingCity is one of the most popular and my favorite site around for all things Vocabulary and Spelling. This is an excellent place for educators to browse or create word lists and even incorporate them into educational games. Also, there is a free mobile app (iOS/Android) that integrates w/ the site for practicing Spelling/Vocab.
I highly recommend checking out SpellingCity by clicking here!!!
*SpellingCity is an advertiser of Technology Tidbits.