Conversion Tools
Conversion tools solve the recurring problem of data existing in the wrong format for whatever you're doing right now — a Unix timestamp that needs to become a readable date, a color specified in HEX that a design tool wants as HSL, a number in base 16 that needs to become base 2 for a low-level debugging session, or a chunk of YAML config that needs to become JSON because that's what your script actually parses. The Timezone Converter and Unix Timestamp Converter are two sides of the same recurring headache: figuring out what time something actually happened, or will happen, across time zones and epoch formats without a math error creeping in.
The format converters — XML↔JSON, YAML↔JSON, TOML↔JSON, Markdown↔HTML — exist because config and data files move between systems that expect different formats, and hand-converting anything beyond a trivial example is slow and error-prone. The Color Converter includes a contrast checker alongside the format conversion, since picking a color that passes accessibility contrast requirements is usually the actual goal, not just getting the HSL values. Text-transformation converters (Case Converter, NATO Alphabet, ASCII Binary, Unicode) round out the set for the more specialized but still real cases — spelling something out clearly over a radio, or checking what Unicode code point a character actually is.