This is targeted to be the most intuitive opensource 2D chemical drawing tool.
You can draw organic chemical structures and reactions very easily and quickly.
Available to download for Windows and Linux (AppImage, Flatpak, Snap)
The Sashimi project hosts the Trans-Proteomic Pipeline (TPP), a mature suite of tools for mass-spec (MS, MS/MS) based proteomics: statistical validation, quantitation, visualization, and converters from raw MS data to the open mzML/mzXML formats.