Arcticons
You can look them up in F-Droid, they have 3-4 versions, dark, light, material you and one that changes depending on the time of the day(dark/light).
PS: it does not work on any Launcher, it has instructions for compatible launchers(20+?) within the app.
Reasons:
In any case I agree with you and I make my gaps as small as possible while still visually sensible. Even on a large monitor there is not much point making gaps larger past some point.