JPEG XL for images because it compresses better than JPEG, PNG and WEBP most of the time.

XZ because it theoretically offers the highest compression ratio in most circumstances, and long decompression time isn’t really an issue when the alternative is downloading a larger file over a slow connection.

Config files stored as serialized data structures instead of in plain text. This speeds up read times and removes the possibility of syntax or type errors. Also, fuck JSON.

I wish there were a good format for typesetting. Docx is closed and inflexible. LaTeX is unreadable, inefficient to type and hard to learn due to the inconsistencies that arise from its reliance on third-party packages and its lack of guidelines for their design.