I only have three fake Pikachu cards, but here they are:
This first one is actually one of the most convincing fakes I’ve seen, except for the fact that it’s a 1st edition (Thin print) Base set card that isn’t Shadowless… 
And no, it isn’t a misprint. The light trick also reveals it’s a fake.
This one has a holo pattern similar to the cards from the Plasma Freeze set, and a vertical cut-line.
And where to even begin with this one… It’s about a cm smaller than a regular card, the colors are too dark (especially the blue in the picture), and the text isn’t even the same as the legit Spanish Boundaries Crossed Pikachu:
Those are the only ones I got so far. Oh, and I have an English Gligar which looks similarly small and bad as the Spanish Pikachu above.
There is actually a fake I want, which is the Base Set holo sticker. Unfortunately it is almost never for sale, and if it is they are asking 200 USD… 
Btw, @justinator also has some interesting Pikachu fakes on his website: www.pikachucards.com/m/collection/contains.php?type=fake#0
Greetz,
Quuador