Here are some resources I found on the internet. If you or your centre have free academic resources, kindly contact me to add in the link.

Free Resources

http://www.chinesealive.sg (Primary Chinese)
https://www.smartguppy.com (Primar/Secondary/JC All Subjects)
https://sgfreepapers.com (Primar/Secondary/JC All Subjects)

Free Resources by Tuition Centres

https://www.bigideaz.sg/composition-writing-tips (Primary English Compo)
https://writingsamurai.com/resources (Primary English Compo)
https://jimmymaths.com/free-materials (Primary/Secondary Math)
https://www.pslemath.com.sg/blog (Primary Math)
https://scienceshifu.com/resources (Primary Science)
https://thepiquelab.com/blog (Primary Science)
https://bluetreeeducation.com/learning-resources (Primary English/Science)
https://selearninglab.com.sg (Primary Math/Science)