Published a while back an entire pack of highly customizable Fireworks for Unity: https://assetstore.unity.com/packages/vfx/vfx-graph-fireworks-vol-1-365818?aid=1100l3Jhu and for Unreal Engine too: https://www.fab.com/listings/ec94bc63-9b06-4bf0-b311-7dc5d0bada90
31 unique customizable fireworks that include Roman candles, Rockets, Shells, Spinners, Bunny hops, Chrysanthemum shells, Willow Shells, Peony Shells, Starglow rockets, Brocade Crowns, Flying fishes, Butterflies, Strobes, Glitter, Planets, Smiley faces, Sparklers, Sparks curtains, Fountains and fire and smoke machines. Easy control over scale and color. Great to build your own fireworks show.