In my mind, there are two aspects of Halloween that lend themselves to the collectable card format really well: the candy, and the costumes.
I’d love to collect one series depicting all the various treats being given out. As a child going house to house for candy, never knowing what you’ll get until the resident answers, really suits the collectable card format. Full-size candy bars would be rare, apples or Mandarin oranges might be uncommon, things like Rockets and mini bars would be common… it would be challenging to fill the rarities, but could be pretty fun. Coming up with unique, original, candy names and logos would be a challenge; you’d want to make the items recognizable but not strictly copy existing brands.
From the home-owner’s perspective, the costumes you see each time you open the door also lend themselves well to the card collecting format. The artist could use the home (or homes’) doorframe(s) as the card frame, showing a view outside the resident’s front door. Each card would be like opening the door to see one or more trick-or-treaters. Lots of variety could be had in designing coustumes, and in their various wearers. Common and/or inexpensive Halloween costumes would make up the set’s commons, with greater rarities lending themselves to increasingly unusual, expensive, or else costumes. Children of different ages, or in different groupings, could also account for rarity changes.
Less exciting to me would be a set depicting Halloween decorations. I’m sure a lot of fun could be had in designing a set of cards for that, too. Simple, cheap, props at common… full-on amateur custom Haunted House transformation at Chase?
I’m getting excited about the upcoming seasonal series. Really looking forward to seeing what this site’s creative artists come up with! There is just so much discovery and surprise inherent to the holiday that would translate well into a collectable series!