The Professor Burnet TG26 card is a collectible because it is the first trading card made of a real person! Professor Burnet was a well-known naturalist who served in the Navy and helped to develop much of Australia's understanding of plants. This card is a symbol of his contribution to society and Australian culture and makes it a sought after collectible. Moreover, the card is a rare item, having been printed only in limited numbers in the 1800s, which adds to its collectible value. The card also features a compelling portrait, with a confident and friendly tone that still interests modern collectors.