Platinum foil, 25x25x1mm, 95%
Platinum is a fairly hard, dense metal often used for corrosion resistant apparatus, jewellery and catalysts. It's also very expensive! For home chemistry it is possible to obtain compounds of platinum at a high cost, but often only a very small quantity is needed to perform experiments, even a single gram can go a long way.
Complexes of platinum are usually either in the +2 or +4 oxidation state and, unlike palladium, the +4 state is of almost equal stability to the +2 state.
This website uses the following compounds of platinum for experimentation:
Potassium chloroplatinite (II)
Chloroplatinic acid (IV)