Below you will find resources for 3rd grade math in general. While many would still be helpful in your multiplication unit, you'll find helpful resources for all of your math units.
https://www.mashupmath.com/blog/mathwarmupactivities?rq=5th%20grade
https://tools4ncteachers.com/resources/district-leaders/documents/AdditionalResourceList.docx
https://www.teacherspayteachers.com/Product/Math-Centers-Bundle-THIRD-GRADE-2235628
https://notsowimpyteacher.com/2021/11/interactive-notebooks.html