I tried all of these out today by myself and then did the mingoville one with Steven and it was really good for him because there is whole section on colors and clothes which is what he is learning now at school.
There are things as simple as letter recognition, phonemes, sight words, etc. These sites would be great for any beginning reader, not just an ELL. So, I know there are a few SPED or elementary teachers out there reading this...these would be great for your kids (and you probably already know about them!!)!