You might thank that I am crazy, but I find many wonderful and research-based activities on Pinterest. You can find just about any activity or worksheet for you child on Pinterest. I will warn you beforehand that there are a lot of TeachersPayTeachers worksheets on Pinterest and those will most likely cost a few dollars per worksheet. However there are many free resources on there as well.
This website has many free printable resources that would be great students to practice at home.
This website would be great to access at home, for those rainy days when your child needs to release some energy.