Let's fill in those missing letters!

[shadowman44]

Hi. It's been a whole year since this thread's been updated. There have been a lot of new systems added within the last year or so!

3DS: J, Q, U,  X, Z
Switch: I, V, Z
PS2: Q, W, X
PS3: #, Q, X, Z
PS4: #, A, I, N, O, Q, W, X, Z
PSVita: #, A, B, F, I, J, K, O, Q, U, V, X, Y, Z
Wii U: #, Q, U, X
Amiga / Amiga CD32: #, H, I, O, Q, U, V, X, Y, Z
Atari: #, L, O, U
Commodore 64: Q, X, Y
Dreamcast: #, A, H, O, Q, W, X, Y
LCD Handhelds: A, E, F, H, I, J, K, N, O, Q, S, U, W, X, Y, Z
LeapFrog: #, A, B, D, E, G, H, I, K, M, O, P, Q, R, U, V, W, X, Y, Z
MSX/MSX2: W
PalmOS: C, E, H, I, J, K, O, Q, U, V, W, X, Y, Z
PC-88: #, J, N, O, Q, U, V, W, X, Y, Z
PC-98: D, E, G, I, J, K, N, O, U, W, X, Y, Z
Neo Geo Pocket: #, A, G, H, J, O, Q, T, U, V, W, X, Y, Z
Plug & Play: H, J, K, O, Q, T, U, X, Y, Z
Saturn: #, E, L, O, Q, T, U, X, Y, Z
Sega CD|: #, A, C, G, H, I, O, Q, U, V, X, Y, Z
SG-1000: # A, I, J, K, M, O, Q, T, U, X, Y
Sharp X1: C, F, J, O, Q, R, U, V, W
Sharp X68000: E
Super Cassette Vision: #, F, G, H, I, J, O, Q, U, X, Y, Z
Supervision: #, I, N, O, Q, V, X, Y, Z
V.Smile: #, E, F, G, H, I, J, K, N, O, P, Q, X, Y
Wonderswan/WSC: #, A, Q, V, X, Y, Z

Personally I don't agree with splitting the Sega CD off of the Genesis/32X because it's technically an add-on and not a standalone console, but whatever I can't argue.