Sunday School supplies I seem to always need

For our Bible Skills and Games Workshop: A kids' play tunnel
Great for races, obstacle courses, and illustrating metaphors

Paper plate and paper cups.
Good for game pieces, art projects, and food of course.

Aluminum foil and old newspaper -- to cover things like tables and foods, and for messy art projects. Foil is also a good sculpting medium and can make a quick prop too.

A blow dryer and a fan for glues and paints that need a little help.

We have a couple of items not yet mentioned that work well with our limited storage and multi-purpose space (i.e. used by outside groups during the week).

puppet theatre made with PVC pipe - this can be broken down and stored lying flat on wall brackets - we label our joints with letters or symbols in nail polish so we can match things properly when reassembling.

felt board and shapes for storytelling - we have some old biblical sets of figures, but find that a simple set of geometric shapes in a variety of coloured felt work really well, especially with the young kids, who can direct you in which shape to use and have no trouble with a rectangle being the flock of sheep.