Made by 3D Artist 兎角.
3D Artist known as 兎角 shared an interesting topology inspired by fellow artist まるい. As they point out, for something low-poly, it does a great job of keeping the fingers looking solid when they bend, and barely any gaps appear.
Here's the reference 兎角 used:
And here's the full model the artist seems to be currently working on:
You should also take a look at oyatsu009's hand rig, which has impressively natural-looking finger movement:
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