meshes
buildings:
9 Terraced-type houses:
-7 front buildings
-2 corner buildings
streets:
5 meshes for road system:
-2 straight - 10 m, and 15 m version
-1 turn
-1 X-shaped intersection
-1 T-shaped intersection

prefabs
buildings:
9 Terraced-type houses meshes each in 5 color version (45 prefabs)
5 set of grouped row buildings (unique colors and mesh variation)
streets:
5 prefabs , each for every road mesh

materials
buildings:
5 sets of color variation
standard pbr with color only, buildings has no textures,
however UVs are mostly unfolded
streets:
1 standard pbr with single gradient texture (512x1px)

System is super easy to arrange. You can extend or reduce number of buildings, each combinantion is possible to set without rescaling.

polycount:
houses
house corner 1 v.11910 p.15248
house corner 1 addon1 v.3753 p.5060
house corner 2 v.7169 p.7326
house corner 2 addon1 v.7434 p.10010
house front 1 v.3101 p.3506
house front 1 addon1 v.764 p.1031
house front 2 v.1748 p.2067
house front 2 addon1 v.759 p.1024
house front 2 addon2 v.48 p.70
house front 3 v.3064 p.3467
house front 3 addon1 v.1284 p.1717
house front 3 addon2 v.163 p.206
house front 4 v.2592 p.3005
house front 4 addon1 v.1576 p.2113
house front 5 v.3433 p.4387
house front 5 addon v.1508 p.2011
house front 6 v.2697 p.3166
house front 6 addon v.712 p.962
house front 7 v.2763 p.2827
house front 7 addon v.1963 p.2632
street
steet straight1 v.7387 p.9998
steet straight2.v.11198 p.15179
steet turn1 v.11136 p.15142
steet turn2 v.8200 p.11214
steet turn3 v.7968 p.10856