Being the competitive family of crimefighters they are, I think the Batfamily would have an annual pumpkin carving contest and the winner would get some stupid prize like bragging rights or Jason’s shoe or something. Regardless, they all take it very seriously.
Dick: He would usually make them into funny faces. Sticking tongues out, scrunched faces, and his favorite, a Jack o'lantern puking up the pumpkin innards.
Barbara: She would carve random phrases into her pumpkins. Things like “Happy Halloween” or “If you can read this you’re too close”. It gets even when she presses a button and it blows up in someone’s face when they lean in to read it.
Jason: Every single year he always makes his pumpkin into the same thing: Himself. He paints it red like his helmet and shoves a gun or two inside the top of the fruit. One year he tried something different and carved it to look like his grave. Bruce didn’t find it as hilarious as he did and he wasn’t allowed to participate in the contest that year.
Cass: Her pumpkins are so pretty and intricate, mostly just pretty patterns with no central theme. They are so detailed they look like they take days. There are swirly designs, detailed patterns, she makes pumpkins into abstract art and wins the contest very often.
Tim: He is a huge nerd, so he makes his pumpkins relate to whatever he is obsessed with at the time. One year he did Start Wars, the next he did LOTR, the next he did Voltron: LD. They actually look pretty cool, despite him being an awful artist when it involves paint or pencils. But give him a knife and he could sculpt you a masterpiece.
Steph: She really thinks outside of the box, abandoning the pumpkin idea entirely and instead carving an apple or a potato. She usually carves meme faces into them and everyone gets a kick out if it.
Damian: He is the artist of the family, so he wins even more often than Cass. His are different every year. Once he did a vampire face, another he did Batcow, and another he did a robin. There’s never really any pattern to what his design will be, but they are no doubt amazing every time.
Bruce: He is a lame dad, so he tries to do a boring classic Jack O'lantern face year after year. They never turn out all that good, looking very much like it was carved by a five year-old. Regardless, his kids always tell him it looks amazing and they put the Bat cowl on it to make it look cooler.