spigot-api topic
NotQuests
Flexible, open & solid paper Quest Plugin [with GUI]
EnergeticStorage
Applied Energistics 2 for your SpigotMC server!
PlotSquared
PlotSquared - Reinventing the plotworld
Glowstone
A fast, customizable and compatible open source server for Minecraft: Java Edition
cardboard
The Bukkit/Spigot/Paper API implementation for Fabric
CommandAPI
A Bukkit/Spigot API for the command UI introduced in Minecraft 1.13
taboolib
Powerful framework for creating multi-platform Minecraft plugin
EliteMobs
This is a spigot plugin that aims to extend Minecraft's survival endgame by making mobs more interesting.
harbor
Harbor is a plugin that redefines sleep within your Spigot server!
Advanced_Bukkit_Coding