Recently I discovered that people have actually started working on Mushroom Kingdom Fusion again, after it was in hiatus for a long time. It used to be maybe my favourite fangame ever, combining all kinds of different franchises while still keeping the Super Mario Bros 3 / Super Mario World style gameplay.
The game still isn't finished but I'm surprised they're working on it at all.
Levels included in this video:
00:00 Intro
00:19 6-S1 Dream Forest
08:28 6-5 The Sky Garden
18:09 6-6 Caverns of Mana (Normal Exit)
32:45 6-6 Caverns of Mana (Secret Exit)
36:54 6-S2 Chrono Chaos