Various programming problems from Codewars, Project Euler, and HackerRank in C#, SQL, Python, and powershell. Simpler problems omitted or consolidated into a single file.
Typically, when exploring a new language or when I start to feel rusty on an existing one (which will happen as career and trends shift), I'll use sites like Codewars and HackerRank to learn and stay fresh. Problems like this also offer a welcome change from life as a corporate developer where nothing ever really feels solved and requirements are far too often ambiguous.