I enjoy Nikoli-style logic puzzles – visual logic puzzles meant to be solved by pure deduction, where no guessing is necessary. If you’re new to these, Pavel Curtis (as “Ada Lovelace”) has written some advice that’s very helpful.
Statues: Statue Park and variants.
Heyacrazy: What if Heyawake used non-orthogonal lines?
Planetary Shading Suite: A set of four puzzles made as a gift for jovi_al.