Fermi Surface for Tight Binding Models
These are Fermi surfaces for nearest neighbor tight binding models arrising from a single s-level. They were produced in Mathematica. Here is a sample code courtesy of Bradley Nartowt:

ContourPlot3D[ -2 Cos[kx] -2 Cos[ky] -2 Cos[kz] == 2.8, {kx, -\[Pi], \[Pi]}, {ky, -\[Pi], \[Pi]}, {kz, -\[Pi], \[Pi]}]

Simple Cubic
E = -2 cos(k_xa) -2 cos(k_ya) -2 cos(k_za)

Simple Cubic, E = -5	Extended Zone
Simple Cubic, E = -4	Extended Zone
Simple Cubic, E = -3	Extended Zone
Simple Cubic, E = -2	Extended Zone
Simple Cubic, E = -1	Extended Zone
Simple Cubic, E = 0	Extended Zone
Simple Cubic, E = 1	Extended Zone
Simple Cubic, E = 2	Extended Zone	Extended Zone Shifted
Simple Cubic, E = 3		Extended Zone Shifted
Simple Cubic, E = 4		Extended Zone Shifted
Simple Cubic, E = 5		Extended Zone Shifted

Body Centered Cubic
E = -8 cos(k_xa/2) cos(k_ya/2) cos(k_za/2)

BCC, E=-7	BCC, E=-6	BCC, E=-5	BCC, E=-4	BCC, E=-3
BCC, E=-2	BCC, E=-1	BCC, E= 0	BCC, E= 1	BCC, E= 2
BCC, E= 3	BCC, E= 4	BCC, E= 5	BCC, E= 6	BCC, E= 7

Face Centered Cubic
E = -4 cos(k_xa/2) cos(k_ya/2) -4 cos(k_ya/2) cos(k_za/2) -4 cos(k_za/2) cos(k_xa/2)

FCC, E = -11	FCC, E = -10	FCC, E = -9	FCC, E = -8
FCC, E = -7	FCC, E = -6	FCC, E = -5	FCC, E = -4
FCC, E = -3	FCC, E = -2	FCC, E = -1	FCC, E = 0
FCC, E = 1	FCC, E = 2	FCC, E = 3	FCC, E = 3.9