Tools
Internal Tools
Game Audio Normalizer and Converter
Allow normalizing the audio files in bulk to 0 dB to make our lives easier, converting them to various different formats, converting to mono, trimming extra silence at the end of each audio file, and fixing clipping at the beginning and end of the sound (by adding a ~10 ms fade-in and fade-out).
External Tools
Free Sprite Editor
Piskel, free online sprite editor. A simple web-based tool for Spriting and Pixel art. Create pixel art, game sprites and animated GIFs.
Photopea
Photopea is an advanced image editor, which can work with both raster and vector graphics. You can use it for simple tasks, such as resizing images, as well as complex tasks, such as designing webpages, creating illustrations, processing photographs and more.