Arabeske is a special kind of vector drawing software. It has a limited set of shapes but is extremely specialised towards complex symmetric interlaced drawings, like those traditionally found in Arabic architecture. It is not a texture editor, but rather a pattern generator. It exports in EPS, PNG, and POV-Ray formats.
Mup produces very high quality PostScript printed music or a MIDI file from a text input file. It can handle almost any kind of music, instrumental or vocal, including tablature, shaped notes, guitar grids, alternate tunings, user-defined symbols, and much more. Mup has been under active development since 1992.
PPM is yet another Game Boy (Color) tile and map editor that uses GTK. It supports many export formats (raw binary, GBDK .c, ISAS .asm, TASM .asm, WLA .asm, and RGBDS .asm), and has different Game Boy Color color emulation modes. It can also import GBTD and GBMB (popular tile and map editors for Windows) files. All mouse buttons draw, and there are loads of keyboard shortcuts. It can also optionally emulate the Game Boy's display.
Lava's jWave is a versatile set of packages for Java that allow you to easily create and process RIFF files, with a special emphasis on reading and writing Microsoft PCM .wav files. jWave was initially released as an integrated feature of Lava, a general-purpose class library for Java. By popular demand, it is distributed in its own bundle.