Hi, back in the 90's in Europe we used to get some original GB bootlegs, not the 32 in 1, 100 in 1, etc cartridges, I'm talking about singular games that came packaged with a box and manual - mostly US boxes and manuals, most had US english boxes but some of them were in gibberish (like that Tarzan GB box someone posted some time ago here thinking it was a proto box). 

A lot of these titles can be identified with the  DMG-WC-USA code, some used the correct codes, but all have cartridges  with a weird font on "Nintendo Game Boy" or even a more purple than grey case (you can see the lower quality of letterings in the case), and all have Made in Japan with Pat. Pend. on the back. Not the newer ones with GAME or GameBoy plastered in the front, I'm talking about the first gameboy bootlegs that weren't multicarts and were available from 1992 (?) - 1998 (?).

Does anyone know how these came to appear on Europe or even show me other titles with the DMG-WC-USA (except ol' Nige's F1 game)?

So far I've seen: Mario land 2 (used to own it), Race Days (own it), TMNT 3 (has the correct US code) - game is in Japanese (neighbour owned it), Donkey Kong Land 3 (grey cartridge I own, heavier than a normal cartridge, came with German box and manual).

They were probably made in Taiwan, right? Who sent them here, were there any companies involved?