One of the many classes I teach to English Language Learners is Geography. It’s a great content class, and can easily be taught in an accessible way. Even if you don’t teach a specific class on the subject, an ESL teacher can easily integrate some geography lessons in a regular English class.
A good teaching tool to use in the classroom is a blank map that students can fill-in. There are many sites where you can get these hand-outs. I have a number of them listed on my Teacher’s Page under the Blank Maps section.