Even as I was writing this post, I coincidentally chatted with a friend on the options for international schools for Student Pass holders. Here are some of my findings. I am putting the disclaimer that this may not be fully correct and you go ahead and cross-verify any information posted here.
For an international school to admit Student Pass holders, the school should have EduTrust certification and this link has the list of schools having EduTrust certification.
In this list, Global Indian International School seems to have the most reasonable fees.