Who could face who
The four best-placed:
WB
WC
WE
WF
A B C D
A3
D3
3B
C3
A B C E
A3
E3
3B
C3
A B C F
A3
F3
3B
C3
A B D E
D3
E3
A3
3B
A B D F
D3
F3
A3
3B
A B E F
E3
F3
3B
A3
A C D E
E3
D3
C3
A3
A C D F
F3
D3
C3
A3
A C E F
E3
F3
C3
A3
A D E F
E3
F3
D3
A3
B C D E
E3
D3
3B
C3
B C D F
F3
D3
C3
3B
B C E F
F3
E3
C3
3B
B D E F
F3
E3
D3
3B
C D E F
F3
E3
D3
C3
Source: Uefa
In the above, WB, WC, WE and WF stands for the winners of Groups B, C, E and F, who are the teams that will play the qualifying third-placed sides.
Who plays who is pre-determined, so the final rankings of the table of the best third-placed teams is irrelevant.
As mentioned earlier, those currently going through, in alphabetical order, are third-placed sides from Groups A, C, D and E.
That would lead to these last-16 ties:
WB v 3E
WC v 3D
WE v 3C
WF v 3A