Bukkit

/register, /login

Allows players to have nicknames.

EasyRanks: A simple Admin-Tool for coloured Tablist and Chat! Take a look at it!

ArchonCrates, the most popular crates plugin.

Morph into any mob!

Scavenger

A plugin that keeps multiple worlds in either day or night!

Manage flying and related commands on a per world basis!

Simple plugin to clear your server's chat.

Speed up Leaf Decay

The official InventorySee plugin by TehCoderHD!

Hub - Plugin

Custom backpack items in vanilla Minecraft!

[1.7.10 - 1.13.2] Similar to popular EnderChest++ but with more features and up to date.

PerWorldChatPlus

Just a simple kits plugin.

SpawnJoin

Only a certain percentage of the players on the server need to be sleeping to change to day

A party plugin for your server bukkit or spigot.

Ping