This site offers enrichment problems for grades k-4 that align with the Saxon lessons. Check out the Math Stumpers for more enrichments.
This site offers a variety of interactive animated videos. Be sure your pop-up blocker is turned off. (in tools)
This site will let you practice number sense, mental computation, and logical reasoning.
This site offers many interactive activities that align with AR SLEs.
Scroll down to How Does Your Pattern Grow for growing patterns practice.
Internet 4 Classrooms
Though this isn't a state specific site, it's very easy to navigate to find links for most SLEs. If you don't find what you need, be sure to search a few grade levels above and below as there are more resources there. There's also a search option at the bottom.