Sorry for the long response, I just want to give genuine feed back.
TL;DR: It'd be nice to see a Smoke or Fire/Flame texture set.
I mainly use Godot.
I'm working on a procedural driving game.
So your recent additions have been amazing.
Godot unfortunately doesn't have an asset store, but it sounds like their sister company might have one in the works.
(after the Unity fallout.)
In terms of formats Godot prefers GLTF, PNG, OGG,
It supports most others, FBX is the one that is has trouble with.
In terms of assets I would like to see.
Well you just added the 2 I needed, Concrete and Asphalt.
I requested the "Generic" Cloth and Armor textures.
Because I find myself stencil painting a lot.
I'm a decent 3D modeler, but as far as painting or drawing I'm like a 1/10.
Stencil painting is basically taking a texture and painting it directly onto a model.
Like the clone brush in Photoshop.
I'm not sure how popular that workflow is among indie devs.
So It may not be worth your time. I'm just throwing out ideas.
But things like flat Weathering, Scuffs, Scratches, Dust/Dirt, Splotches etc. textures would be useful.
They'd also be useful as Decals in scenes for making rooms look lived in.
(We finally got Decal support in Godot 4.0)
That's also getting into the FX territory.
So like Fire, Smoke, Ice particle effects.
And those are typically just flat sprites like you did for your foliage pack. (which was absolutely amazing by the way.)
I'm fairly certain there's a market for FX sprites.
A lot of what I suggested above could be pulled off by adding animated image masks to your existing textures.
(Or animating a cut up 3D Plane with the texture applied, which is how I do it.)
So really you're only missing a good Smoke or Fire/Flame texture.