Added a few textures for the terrarin from open game art. They'll need to be color corrected a bit, but it's perfect for now.

game/data/voxel_surfaces/1_stone.tres

@@ -1,11 +1,12 @@
-[gd_resource type="VoxelSurfaceMerger" load_steps=2 format=2]
+[gd_resource type="VoxelSurfaceMerger" load_steps=3 format=2]
 
-[ext_resource path="res://data/voxel_textures/test_11.png" type="Texture" id=1]
+[ext_resource path="res://data/voxel_textures/test_09.png" type="Texture" id=1]
+[ext_resource path="res://data/voxel_textures/test_11.png" type="Texture" id=2]
 
 [resource]
 resource_name = "Stone"
 id = 1
 voxel_name = "Stone"
-texture_top = ExtResource( 1 )
+texture_top = ExtResource( 2 )
 texture_bottom = ExtResource( 1 )
 texture_side = ExtResource( 1 )

game/data/voxel_textures/test_03_readme.txt

@@ -0,0 +1,9 @@
+From: https://opengameart.org/content/seamless-2
+
+Author: 
+arikel
+
+License(s): 
+CC0
+
+Thanks!

game/data/voxel_textures/test_06_readme.txt

@@ -0,0 +1,11 @@
+From: https://opengameart.org/content/handpainted-stone-wall-textures
+
+
+Author: 
+PamNawi
+
+License(s): 
+CC-BY 4.0
+CC0
+
+Thanks!

game/data/voxel_textures/test_09_readme.txt

@@ -0,0 +1,10 @@
+From: https://opengameart.org/content/handpainted-stone-tile-textures
+
+Author: 
+PamNawi
+
+License(s): 
+CC-BY 4.0
+CC0
+
+Thanks!

game/data/voxel_textures/test_11_readme.txt

@@ -0,0 +1,9 @@
+From: https://opengameart.org/content/seamless-2
+
+Author: 
+arikel
+
+License(s): 
+CC0
+
+Thanks!