(define my-collection ' ( 🌱 ☀️ ☔️ ))
(set! my-collection (cons '🎥 my-collection))
(set! my-collection (cons '🐧 my-collection))
my-collection
  → (🐧 🎥 🌱 ☀️ ☔️)

;; save it
(local-put 'my-collection)
  → my-collection