Here are some adorable Hello Kitty-themed party favor ideas to consider:

1. Hello Kitty Goodie Bags: Fill cute, personalized Hello Kitty bags with small treats like candies, chocolates, or themed cookies. You can find these bags or even create your own with Hello Kitty stickers or prints.
2. Hello Kitty Stationery Set: A mini stationery set featuring Hello Kitty designs—pencils, erasers, notepads, and stickers—makes a practical and charming favor for guests of all ages.