As long as it's on my brain, another resource that I like for preschool are Kumon books. Each book is designed by specific skill. Depending on what a child needed work on, they are bright, colorful, specific and engaging.
Two that I would gear specifically for preschool would be the Cutting workbook and the Tracing workbook. We own the cutting workbook and Luke LOVES it. Learning to use scissors is quite the skill, and each page gets harder in difficulty from the next, so progress is slow but cutting is still fun. For similar reasons, the tracing workbook is great for learning how to hold a pencil correctly and increasing fine motor skill.
For the price (under $7 a book), I think these workbooks are a great investment, especially since they key-in on a skill that might need extra work.