Just noticed the IO implementation on fireworks and realized the firework selection is fairly dim. SO! some new fireworks would be rad I think! A box of poppers for itembar use, big box displays, those little ground fireworks shaped like various vehicles. Could make a whole selection of holiday ones even. Jack-o-lantern shaped sky rockets. Snowflake themed ground sparklers etc etc. heck maybe even some actual magic fireworks full of bats and real snow.
A pitch I think would make for some fun IO options as well as some fun holiday items to collect.