Tons of super cute printables for early learning students. Coloring pages, flashcards (including some for Spanish), file folder games, crafts, and activities. The graphics are really really cute.
Enchanted Learning has thousands of great printables for just about any topic. The range from PreK to older elementary and cover every academic topic. They also have pages of craft ideas and instructions, and an online interactive calendar featuring lesson plans for each day of the month. There is a paid membership required for some of the prinables and many of them print out much nicer (and easier) if you have a paid membership. Having the membership has been worth every penny for me. You can view all of the printables in thumbnail first so you can be sure you'll be getting your money's worth.
Crayola is another really great site with loads of free printables. They have all of their printables broken down by subject. They include regular coloring pages, games and activities, state information pages, alphabet pages, Disney, and make and play. Their website is really easy to use and everything has a thumbnail so you can scan through your options quickly. There is also an activity studio where you can design some of your own printables.
They offer a pretty good selection of free printable Montessori activities. It changes frequently so it's a good idea to check now and then.