rFXGen is described as 'simple and easy-to-use fx sounds generator, based on the amazing SFXR. Sounds could be saved as .rfx (sound generation parameters) and also exported to .wav as sample data, defining sample formatting' and is an app in the Development category. There are nine alternatives to rFXGen for Online / Web-based, Linux, Windows and Self-Hosted solutions. The best alternative is bfxr, which is both free and Open Source. Other great apps like rFXGen are SFXR (Free, Open Source), LabChirp (Free), ChipTone (Free) and sfxia (Free).
Bfxr is an online version of sfxr, a chiptune sound effects generator. The interface is more or less the same as sfxr. Some additional features have been added to this version such as 5 new waveforms, 3 new filters, a mixer, and more.
Sfxr is a program that specializes in making chiptune sound effects for video games. Its interface consists of sliders that change the shape of the wave as well as the envelope and pitch. It has the ability to export to WAV for use in other programs.
LabChirp is a Windows tool to help you create sound effects, for games, music, videos and more. Features Multiple channels: Up to eight individual channels. All or any element of a channel can be copied to another.
Industrializer is a program for generating percussion sounds for musical purposes. This program is great for generating new techno and industrial sounds. It also can produce chimes, bubbles, gongs, hammer hits on different materials and so on.
wafxr is a sound effect generator in the tradition of as3fxr, bfxr, jfxr, and others. But where such tools normally generate static files, this one plays sounds dynamically via Web Audio. Supports oscillators, FM synth, tremolo/vibrato, and various other filters and effects.