ClassiCool

If you like Sonic then definitely check out the Spark the Electric Jester series. Spark 1 is all 2D, Spark 2 took the series into a 3D direction and Spark 3 heavily refined the gameplay of the previous game. Make sure to keep an eye on Rollin' Rascal during its development as other than Haste that's the only 3D Sonic-like I can think of.

I've released version 1.1 of this plugin which allows for much greater customizability! You can adjust many properties across different terrain generation stages through the power of JSON and I even sneaked in a new level type.

For people who have tried to get this plugin working on Windows, I did a couple fixes so that it works now. I've only tested it on Linux :P

Indev Adventure has come to ClassiCube! Indev Adventure is a mod for Minecraft Indev that adds in 9 level types, 7 level themes and 3 structures. This plugin allows you to use that mod's world generation inside your own MCGalaxy server! Simply drop the C# file into the plugins folder, run '/pcompile IndevAdventureGen' and '/pload IndevAdventureGen' and you're good to go! To learn about how to customize it, type in '/help newlvl IndevAdventure' for a list of arguments, types, themes and structures. Indev Adventure uses a system of terrain generation stages that are layered on top of each other and can be mixed and matched in different ways. That means that it is very easy to make your own types, themes and structures in the code. Source code: https://gist.github.com/BlueStaggo/6ce053244f1f65fe131cd535dbde690e

This is sure to attract more players onto the game. People might search up something similar and see this. Probably that's the reason why you did this, or it's for the money, or both.