Musically inclined teachers can do Pop song club (or just music club to have more freedom). Learn English songs, singing methods, basic rhythm, even musical theatre to an extent is possible.
Also dance club might be fun. I go to a dance hagwon and the students (who normally are not interested in English at all) are excited to relate it to what they already like doing. We have mini lessons on terminology in English (like marking, from the top, leap, stretch, point your toes, etc.). Lots of good verbs to use. This sort of club could be for any sort of sport really. English PE club!
Video game club - again, they're already interested in it, so there could be a club on English terminology in video games or something. I guess with elementary you'd have to be careful with appropriate material though.