Wow, I don’t even know where to start on this site…
http://spanishflashcards.tripod.com/
You’ll notice several columns, and as you scroll through each, there is so much information in a variety of areas. It could be printable cards that show examples of stem changing verbs or activities with vocabulary (flash-card related). There is a lot of content here. Ser and Estar is here. Preterito is here! There are a couple of links to textbooks like Realidades I and II. Vocabulary topics like animals, colors, alphabet, house, clothing, family and food are prominent. Check it out!!