From my personal collection: ($10 apiece when nobody wanted the things at an auction)
The early days, pre restoration.(still in progress)
Asteroid Fighter Deluxe:

Some sort of weird plastic panelling glued to the original sides
Galaxia Whiz:

It was a galaxian.. still has the original burn in. At least it is restorable.
(yes, it is going back to something original, Galaxian fans.. )
I took great pleasure in removing the z80s from that thing for use in me Galaga.
They are much better now, but still a bit ugly. The AD is black now.
..and Centipede Fighter 2:

No, that's not permanent.. I was just having fun when I realized the panels would swap out.
(Centipede had a wood-grain CPO.. and the sides were painted black.. but it was free.
it's going back together as a proper one, having collected all the parts short of the art and start buttons,
and I found a (artless)bezel for it since the picture was taken.)
2 out of the 3 will be going back to something resembling the original.