I feel like there should be two tiers between the last two with something like an Assaultron and then Protectron from Fallout. It seems a bit of a stretch to jump from "Explicitly feminine, explicitly mechanical" to "Not remotely feminine, explicitly mechanical" without the stopgap of "Vaguely feminine, explicitly mechanical" and "Vaguely humanoid, explicitly mechanical." So I would order the tiers from 2B to Toaster:

1. Explicitly feminine, implicitly mechanical – Obviously a girl, 0 to negligible visible mechanical features. – 2B, D:BH Androids.
2. Explicitly feminine, vaguely mechanical – Obviously a girl, mechanical features can be confused for armor. – Whoever the girl in the picture is for (2).
3. Explicitly feminine, notably mechanical – Obviously a girl, has some visible and undeniably mechanical parts. – Aigis
4. Explicitly feminine, explicitly mechanical – Obviously a girl, almost entirely made of metal/synthetic materials and mechanical parts. – Jenny/XJ9, the Nandroids
5. Vaguely feminine, explicitly mechanical – Has an effeminate design, possibly including wide hips and a notable bust, but isn't designed to look explicitly like human in appearance. – Assaultrons
6. Vaguely humanoid, explicitly mechanical – Has a somewhat humanoid "shape" but is very clearly not modeled on actual human anatomy. – Protectrons
7. ??? / Not remotely humanoid, explicitly mechanical – T O A S T E R

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The line between Slight Robot Fucker and Robot Fucker is very slim