Had when i worked in a preschool and kids love them! I would use colored sand instead of white salt. DIY salt tray with alphabet cards. Easy to make and kids have fun smoothing out the salt after correctly making the letter
Structured alphabet sensory table task: magnetic letters hidden in coloured rice with scoops and shovels. Matching letters are stuck onto baking trays (attached to the wall with velcro). Hunt for the letters & stick them onto the corresponding letters.
Pom poms, tweezers and sounds as an alternative to water in the water tray! Even added some CVC pictures for my uppers and the found the right sounds to spell the word and put then on a magnetic whiteboard which was hanging up on the side of the tray! Great for fine motor development, sorting sizes, colours and counting too!