In discrete mathematics (combinatorics) there are definitely some tools and techniques but seemingly every problem is unique, I’m not quite sure that pattern matching is very useful in this subfield of mathematics ?
Discrete math is frequently about things with very little structure (e.g. graph theory, where you basically just have any binary relation), so inevitably ends up trying to prove things that are way too general. The flipside is that those theorems do tend to crop up everywhere.