New stuff for the list, no idea if it's there already but here we go:

Panasonic FS-A1 MSX2 Adapter:

Unique male end connector: instead of prongs, there's three holes. Plug shape is odd, sort of like a triangle affixed to a square. Prongs are really tough stuff, so if they're bent (like mine) you won't be able to bend them back.

From the label:

AC ADAPTOR FS-AA51
(input, I believe; label for this entry is in Japanese) AC100V 50/60Hz 23VA
(output) DC9V 1.2A
AC18V 170mA

Sega Nomad power adapter

Odd end to the plug that fits in the Nomad with yellow tip; little spot in the center with a keyhole shaped space. From the label:

Model MK-2103
Input: 120V AC 60Hz 15W
Output: 10V DC 0.85A

(-)--(C--(+)

(How do I read this shorthand?)

Philips CD-i 370 ("handheld" unit)

Box-on-a-cord style; plug is rounded on one end and flat on the other. From the label:

AC/DC Adapter Model 22ER9159/17
Input: AC 120V, 50/60Hz, 45W
Output: 21V === [Similar to that but the top line is connected all across) 1.7A

That's all I've got in the way of even slightly unusual plugs.

Sorry for the lack of more technically comprehensible language but that's the best I can do.