Post saltybets, interesting characters, and so on. You can make your own fighters using a program called Fighter Factory, of which there's plenty of versions. Mugen comes with a base character called Kung Fu Man, who has all the features of the engine attached to get you started, just import him into a program and study him a bit and you can start making shit like this.
On top of that there's nothing wrong with using someone's character as a base, so if you think someone's spritework sucks or they can't design for shit, you can take their character and redesign it yourself using their spritesheet, which you can export using these programs. So if you want to make, say, a full Resident Evil fan fighting game, you don't have to work from the ground up.
One of the reasons i'm bringing it up is that kids from the new generation have been making fighters for this engine. Like nu-Cartoon Network characters, so if you want to make a legit fighting game, you have no excuse and this engine is the perfect place to get started.
