A bunch of (configurable) ingame random spawn messages:

Ingame Help Menu:


New command since v1.2.0:
/rp spawnrandom - Spawn a random rainbow at a random location (with a leprechaun) without having to wait for the random rainbow interval. (permission: rainbowspro.spawnrandom)

bStats (since v1.2.0 - 2022):
https://bstats.org/plugin/bukkit/RainbowsPro