You want a fully customizable Firework Show with frames and delays? Guess what, you found it!

Originally named Ultimate FireworkShow by igufguf!

Original Creator: igufguf Being Maintained (Possibly forever?) by Jackietkfrost and Zuwel

Updated for version 1.16.3, Hasn't been tested on earlier versions.

Commands
Aliases: /fireworkshow - /fws

• /fws play <show-ID>
  • Start a firework show
  • fireworkshow.play
• /fws create <show-ID>
  • Create a new firework show
  • fireworkshow.create
  
• /fws delete <show-ID>
  • Delete a fireworksshow
  • fireworkshow.delete
• /fws addframe <delay>
  • Add an empty frame to the show, delay is in ticks (1 second is 20 ticks)*
  • fireworkshow.addframe
  
• /fws delframe <show-ID> <frame>
  • Delete a frame
  • fireworkshow.delframe
• /fws dupframe <show-ID> <frame>
  • Duplicate a frame to a new frame at the end of the show
    
  • fireworkshow.dupframe
• /fws newfw <frame>
  • Add the firework in your main hand to the last frame on your current position
  • fireworkshow.newfw
  

• /fws highest <true/false>
  • Specify whether the firework will launch from where it was initially added to a frame or if it will launch from the highest block above or below it.
  • fireworkshow.highest