I'm not OP but I've used this brand several times and they're really cool. They last a long time, too. You just chuck the individual packets (DO NOT OPEN) onto the fire.
Magical Flames Color Fire Packets - 25-Pack of Fire Colors for Campfires, Fire Pits, Outdoor Fireplaces - Hue-Changing Cosmic Flame Powder - Camping Accessories - Stocking Stuffers for Kids & Adults