This list is for your reference. All materials will be supplied by me and Head-Royce.
assorted rubber bands
plain unlined paper
corrugated cardboard (cut up boxes)
Fairly easy to find -- shop around:
(available in wood or plastic.
Avoid the "foam" ones, because in my experience they are less accurately manufactured)
pentominoes (based on 1-inch squares.
I recommend pentominoes that are not scored between the squares, but unfortunately, they seem to no longer be available.)
If you are not interested in circle geoboard activities, 11 by 11 geoboards are easy to find with many publishers.
Polydron Frameworks Archimedean Solids (starter set, will make any Archimedean solid | class set, will make all of them at once)
Available only from me: