Things a plangonologist collects

The crossword question “Things a plangonologist collects” can be answered with the word “DOLLS“. A plangonologist is not a real word, but it seems to have been constructed from the word “plangology” which means the study of dolls. So, someone who studies dolls or collects them would be a plangonologist. Therefore, the answer to the crossword question implies that collecting dolls is a common activity of plangonologists.