Ok, I had some more time to take some pictures. I took some pictures of real cards on the left, and fake cards on the right. I will also mention why they are fake when you compare them to a real card.
First of all a picture without comparison to a real card, because all these artworks doesn’t exist on real cards (except for the Pokémon Illustrator one; could someone who owns a real copy borrow it so I can take a comparison picture? 
).
The cosplay Pikachus and Ancient Pikachu are custom made by the same artist (and the only fake cards I ever bought willingly, because they look pretty amazing - especially the big-headed Blastoise).
So here is the first tip already: always look up the set number on Bulbapedia (or similar websites) to check if it’s indeed an existing card.
As mentioned before, these Cosplay Pikachus have the rainbow-like gloss to them. They are also very sticky due to the material used to create them. I know you can’t feel a card when you look for them online (which is unfortunate, since a lot of the cards to follow are also very obvious fakes when you touch them).
So, what is wrong with this card?
- First of all, the font at the attacks and weakness/resistance/retreat cost are different than the real card
- The black parts of the (Metal/Normal/Fighting) Energy symbols are too big
- It’s non-holo, even though the background of the artwork implies it’s holo (NOTE: Although I don’t have confirmation yet, I’ve heard rumors that a non-holo version of this Secret Rare Pikachu does indeed exist, released in a Swiss magazine. Unfortunately I can’t find the source where I heard about this anymore; and more unfortunate: I don’t have it in my Pikachu collection.)
- The colors of the metal card are too light
- Weird holo pattern in the artwork
- Missing the lightning bolt at the attacks (note that this also happens sometimes on real versions of this card, where the lightning bolt is so shallow that it’s almost not visible)
- The colors of the lightning card are too dark
- The rarity and set symbol aren’t holo
Both on the left are real, right one is fake.
- Much darker colors than the real card
- I don’t know if the fake is Spanish or Portuguese, but both real cards have different texts for the attacks and attack description either way
- The card is smaller than the real cards, which was the most obvious thing with this fake
- The Lightning Energy symbols are of a different color and layout
- It’s name is Raikou EX instead of Pikachu EX…
- It’s non-holo
- The (Lightning/Normal/Fighting/Metal) Energy Symbols are different
- The font (especially noticeable at the attack numbers) are incorrect
- It states “Over Spark” instead of “Overspark”
Both at the left are real (regular & miscut version), the three at the right are fake.
- The first one which is holo is much more 3D than the real one
- The other two are non-holo instead of holo
- The Normal Energy Symbols are wrong
The left one is real, the three right ones are fake.
- The holo one is pretty obvious, since no holo pattern like that exists
- The others have an incorrect Lightning color again
- They also have incorrect font, as well as the Energy Symbols
Left one is real, other two are fake.
- Same things to note as the two Flying Pikachus above (since they are from the same fake sets)
Both left are real, both right are fake.
- The Reverse Holo isn’t the same Reverse Holo we’re used to, as you can see in the picture from the shine of the two cards. The real Reverse Holo has a much nicer reflection, while the fake one has no reflection at all.
- In addition, the entire card is holo, including the artwork and borders of the card which are non-holo on real Reverse Holo cards
- The non-holo fake has the outside of the XY Evolutions Pikachu, with the picture of the Furious Fist Pikachu… So it has an incorrect set symbol; incorrect attacks; etc.
Left one is real, other two are fake.
- The fake ones are non-holo
- The first fake one has three Normal Energy Symbols instead of a Lightning and two Normal Energy Symbols for the attack “Overspark”
- The second fake one has yellow borders instead of black
- The entire layout of the left one is the same as the Japanese version, instead of the English (here is a picture of the real Japanese card as comparison)
The two on the left are real (with light and darker purple backgrounds in the artwork - I also have a real one with blue background which isn’t in the picture above)
- The holo I don’t have to discuss…
It’s thinner, weird holo pattern, and a sticker. - The other three all have different colors (either too light or too dark)
- They also have incorrect fonts
- The bottom one has grey text instead of black
- The outer right one has incorrect alignment (like the HP) and sizes of the text
- As mentioned at the start of this post, you can also feel the difference very clearly with all the XY Evolution Pikachus (including the Flying/Surfing) very clearly
- This one actually looks very close to the real one. Only the borders are different, and the thing that proved it was fake was the flashlight test
- Oh, and it’s non-Glossy while this card only exists as Glossy (a.f.a.i.k.)
(I might redo this picture and add a regular unlimited Base Pikachu as well when it is lighter in my room again - it’s evening now.)
- Again one that looks not too wrong. Compared to the 1st edition Shadowless card, it obviously has different font-size (especially noticeable by the additional line on the “Thunder Jolt” attack), but these same differences apply to a Shadowless vs Shadowed Pikachu.
- The colors of the border are different, but with the Base Pikachus this happens often on real cards as well. Here is a picture of some of my real Base Pikachus for example, where you can see a lot of different colors. And here is an example of a real Orange-bordered Base Set 2 Pikachu.
- But the most obvious thing: it’s a Shadowed card with a 1st edition symbol (and it isn’t Machamp).
- This card also fails the light test, but feels pretty real compared to most of the others above.
So, those are all the fake cards I own compared to the real ones. If you have any questions feel free to ask. 
Greetz,
Quuador