I recently finished a bigger sandbox in our backyard for my kids. I wanted to incorporate some materials in and around the sand box that would allow for more open ended play. The nature of sand itself encourages many ways to play. You can use it wet or dry, build with it, pour it, move it, feel it and more! By gathering different elements near your sandbox, you are encouraging all kinds of creative uses!
Age: Under 5's, 5-10's
Sandbox or sandpit
Natural elements - rocks, shells, cones, tree branches, logs, sticks
Household elements - measure cups, muffin tins, old pots, strainer, old spoons
Building elements - wood pieces, blocks, bricks
Add unlikely elements to your sandbox. Kids will never tire of a bucket and shovel but these toys generally have a specific use (although some kids can think of others!)
Put cones, shells and rocks in terracotta pots by the sandbox. They can be left at the side of sandbox, easily drain and provide a place to put items when not in use.
Have some sticks available for making castles or roads.
Find old kitchen wares that can be used in the sandbox. Kids love to play with the "real" thing.
If you are up for a bigger challenge, put logs around the edge of the sandbox. My kids have used them for stepping stones, stools, as part of a castle, or even to bake on.