During my childhood, it was common to collect stamps or coins or action figurines. Given how the Internet and social media have radically changed our habits these days, collecting physical items seems to be an outdated, old-fashioned activity. Nonetheless, collecting postcards sold by JP Post (https://www.postacollect.com/gotochi/) could be a fun thing to do and create indelible memories for your trip. These postcards highlight the signature delicacies/festicals/landmarks of a prefecture, so this means that the ones that you buy at Tokyo will be different from their counterparts at Kyoto.
Yes, this means that the first place I hunted whenever I visited a new prefecture in Japan was a JP Post office. Buying these prefecture-specific postcards marked the first conquest I accomplished successfully and made me feel closer to my destination, even though I had not actually done anything of significance yet.
I used to paste all these postcards in the form of the map of Japan on a wall of my apartment. It was a vibrant reminder of where I had travelled in Japan and motivated myself to continue my earthly adventures.
What do you collect? How does it inform you about the world?