Before you hit "download," understand the climate. The scene exists in a legal grey area. While M.U.G.E.N. itself is freeware, the sprites are usually ripped from commercial games (Capcom, SNK, Arc System Works).
Pro tip: Download screenpacks labeled "18- Screenpack" first. These modify the UI to display mature art, enhancing the experience. 18- edits - Downloads - The MUGEN ARCHIVE
: Look for sub-categories such as SNK Multiverse , Athena edits , or Kula edits for specific character types. Before you hit "download," understand the climate