Abandonware Puzzle games
Puzzle games focus purely on solving puzzles usually without much narrative. Puzzles exist in many varieties: strategic, tactical, logical, trivia, word puzzles etc.
In the Puzzle genre, you may want to play 1993tris, 3D Lemmings Winterland, 3D Pitfall, Adventures of Lolo, Adventures of Lolo 3. Those are just suggestions, you are welcome to download any game!