A lot of games, especially small ones by small creators, borrow heavily from the visual style and design language of an iconic original. The levels of directness can vary, but it is very often quite obvious.
It seems to me that perhaps the most common such inspiration is Legend of Zelda: Link’s Awakening DX. Blocky pixels. Distinctive looking approaches to trees, as well as a particular method for representing perspective and ridges/height levels. Typically thick black outlines and two other colors, most likely white or another pale neutral color to help them pop (though the background sprites might have a dark but lower contrast outline color). It’s unmistakable. Most of them look like they could easily be a screenshot from another GBC installment following the Oracle games.
Here’s a few.
Isles of Sea and Sky
Chico’s Rebound
Mina the Hollower
