With the SMBX Magic Patcher you create a patch of a smbx level file which can be apply on a other smbx level files. This is usefull for scirpt submissions e.g. The SMBX Magic Patcher has a userfriedly GUI. It use a own file format: .plx (= SMBX Magic Level Patch). It supports .slp files (= SMBX Lev...
MSPaint (7-10/Vista/XP/98 versions/PBrush) for marking transparent spots with purple, MarioShop/GreenFish Icon Editor for "cutting" the sprites out and GFIE (again!) for making cursors and icons. EDIT: GFIE somehow seems to combine the powers of RWCE (RealWorld Cursor Editor) and Junior Ic...