7 cases
Permute the last layer in two steps with six algorithms instead of twenty-one.
Corners first, then edges. Two algorithms handle every corner case and four handle every edge case, so six algorithms finish any last layer. This is the natural stepping stone to full PLL, and the algorithms are all part of the full set — nothing learnt here is thrown away.
Every edge is already home, so each side shows its own colour through the middle. One corner is home too; two matching corner stickers mark the face to hold at the back, and from there the back-left corner travels to the back-right.
Indistinguishable from Aa at a glance: edges all solved, one corner home, one set of headlights — on the right in the diagram. Turn them to the back as you would for Aa and the cycle runs the other way: the back-right corner travels to the back-left.
All four edges solved and not one set of headlights anywhere — no two corner stickers on any face match. That combination happens for E and nothing else. All four corners are wrong, swapping in pairs.
All four corners are home, so one side is a solid bar of its own colour and the other three show headlights. The three wrong edges cycle anticlockwise: with the solved edge at the back, the front edge belongs on the right.
The same picture as Ua — a solid bar on one side, headlights on the other three — with the cycle running the other way. Hold the solved edge at the back and the right-hand edge belongs at the front.
Four sets of headlights, and every edge belongs on the face opposite the one it is sitting on. The case looks identical from all four sides, so there is no angle to hunt for.
Four sets of headlights again, but the edges have swapped with their neighbours rather than their opposites: the front edge shows a side colour, not the back colour.