Group activity crackers like the handbells, indoor fireworks and wind up toys are always fun. John Lewis have a xylophone set. Normal crackers are just filled with plastic tat destined for landfill and, even if you get the luxury ones, there is a limit to how many egg cups, mini nail clippers and picture frames any family needs.
I make my own and fill them with small gifts that the person might actually want - small toys, puzzles, mini perfumes (advent calendars reduced after 1 December are good for getting supplies), soap, face masks, make up, bath pearls, kitchen gadgets (strawberry huller, nutmeg grater), incense, fragrance oil, key rings, plectrums, USB sticks, seeds, earrings, hair accessories, miniature bottles of alcohol, luggage labels, bookmarks... Then I add wrapped penny sweets to fill the space. The year I bought American sweets from the world food aisle at Tesco went down really well.
You can get kits online (they often sell the gifts too) from cracker suppliers or Amazon. John Lewis sells pre-assembled fill-your-own crackers too (they already have the hat and joke inside).