I have some scripts that are longer than 16,000 px (in screenshot form), but I can't say I'm proud of them. When programmers want to show off their skills, they usually do the opposite--try to write code that accomplishes elaborate tasks in as few lines (or blocks) as possible. Look up "code golf" sometime.
Since you asked for long scripts, though, I'll share mine. It's the animations handler for
"Rogue of Vallas". Animation handling tends to grow exponentially more complex as the number of different states increases.
This thread would probably be more interesting if we talked a little bit about what the script does, features we're proud of, lessons to share, that sort of thing.
One thing I am very glad I did with the custom block "reset animation" is add a "caller" argument. This is only used for debugging, but it prints the event that triggered the reset. This has been invaluable for debugging animation states. When something happens, the current animation often needs to be reset. As complex as the animation handling is, there is a lot of room for logic errors. Knowing which event called for an animation reset has made fixing these errors a lot easier.