How about foldback clips? Makes for a mini-Zettelkasten to-go :)

https://www.amazon.com/Coideal-Bulldog-Picture-Document-Kitchen/dp/B07B92NH1R/ref=sr_1_9?keywords=foldback+clips&qid=1669929173&sprefix=foldback+c%2Caps%2C1203&sr=8-9