In-game panel: enter the resources you have (items and fluids), and instantly see every recipe you can craft with them. Features deep search (everything derivable in chain), 'missing 1-2 ingredients' mode, name search, pinning, grouping by machine/tab/ingredient count, and a ratio helper in the tooltip. Great for packing more production onto a single line without searching by hand.
Providing the player with new tools or adjusting the game interface, without fundamentally changing gameplay.