For instance. And most likely also texture quality (“higher resolutions” take up more memory, naturally). So in fact pretty much everything that increases the geometry / triangle count and number and resolution of textures.
Various anti-aliasing algorithms may also profit from more VRAM (especially “temporal anti-aliasing”, as this probably requires data from several consecutive frames - but I am not an expert and can only assume what those algorithms do in detail - would have to educate myself first), but that amount may be neglegible when compared to texture / geometry (and is probably more or less “constant” and correlates with your screen resolution).
Oh and yes, screen resolution also affects the required VRAM 