Alchemy: Free PDF File Converter App

Alchemy is an impressive, open-source file converter built on the reliable Electron and React. It offers a variety of operations, including the ability to merge files into a PDF. Its features include an elegantly simple, drag-and-drop interface for converting and merging files, as well as the option to merge multiple images into a single PDF, with the added benefit of being able to change the file order.

Additionally, it allows for batch conversion of multiple files to various file types, making it a versatile tool for any user's needs.