This is a topic of great interest to some, and zero interest to others.
I enjoy having unusual cards in my deck, whether altered, signed, textless, foil, or foreign. Plus, I make my own generals! Not everyone likes having these types of cards, and I understand that. It's annoying when someone plays a card and there's no text, or altered to cover the text, or in a different language.
I have had the experience of needing to look up my own card and finding out that it doesn't do what I thought it did. Egg on the face and all.
So let's go over the things you are going to find.
Foils
This is the most common form of pimping out. I'm in the process of foiling out my Vampire deck, and it's a slow and surprisingly expensive process. Well, maybe not too surprising considering how some prices have gone crazy lately.
There's a lot of factors that contribute to the rarity of foils, and one of the main ones is Legacy playability. If it gets played in Legacy, a several-thousand-dollar format, then those players will always chase the rarest versions of cards.
Case in point: Brainstorm. There's only one version of this in foil, and the prices for that Mercadian Masques foil are astounding.
The age of the set and the foil is another major factor in the price. Urza's Legacy was the first set to have foils, and the rares, commons and uncommons can have some impressively high prices.
For EDH players, since we have need for only one of a card, we tend to chase the original set foil, often referred to as a pack foil. The M13 foil of Rancor is one quarter the price of the Urza's Legacy foil.
As someone who was playing when they introduced foils, we thought it was a Pokémon flash in the pan and kind of a joke. I remember discussions that focused on how the foils were a different color, they looked worse, and were actually LESS valuable.
We were not aware of what would be happening in twelve years.
Another kind of foil that's worth knowing about is the assorted promotional foils. We have:
Arena League
Junior Super Series
Prerelease Events
Release Events
Game Day full-art foils and older textured foils
Magic Player Rewards Textless foils
Friday Night Magic
Judge Foils
Buy-a-Box cards
Resale promos
Pro Tour foils
Grand Prix foils
Special Event foils, such as the Wizards Holiday cards, e.g. Snow Mercy
Duels of the Planeswalkers promos
Foil-only editions, like Commander's Arsenal or From the Vaults
Duel Decks foils
And the rarest of all, the Exodus test foils. More info here.
Generally speaking, people want original set foils for their pimped-out decks. After all, when you're spending $50 on a card, why not spend some more and get the oldest one?
There can be different art on a promo foil, and that's sometimes a factor. Mostly, though, we want the rarest, and that's usually the pack foil.
Judge foils are something that you can enjoy or not, and mostly it'll be because of the art. Wizards doesn't pay judges directly for being judges at large tournaments, except perhaps for the highest-level Head Judges. Instead, judges are given promotional foils that can be worth significant money. The beginning of a season is when these cards go for the most money, and being patient can result in these cards being lots cheaper.
When we went to the World Championships in November 2011, a friend of mine laid down $100 for a judge foil Xiahou Dun, the One-Eyed. Now that's about $25. He's enjoyed it, and that's what is important, but keep the finances in mind.
Some of the early judge foils are of cards which weren't available in foil before, and are often prized by those who want to foil out their cube or deck. The judge foil Gaea's Cradle or Swords to Plowshares are big money indeed. But they look awesome, especially if you recognize what they are worth.
Early Editions
Since Alpha cards have a more rounded corner, they aren't always allowed in tournaments, since even in sleeves, a difference can be noted. Each Head Judge has to make that determination. What this means for EDH players is that sometimes, there's a difference in price for the editions that we can't explain, and that we might be able to get an Alpha cheaper than a Beta. Because of collectors, though, Alpha prices are starting to go wild and this difference is disappearing.
Beta cards, if you want early set cards in your EDH deck, are the ones to chase. Wrath of God, Swords to Plowshares, Demonic Tutor...these look amazing as aged Beta cards. The original dual lands look great too, and while Beta isn't the only way to get black-bordered dual lands, I can tell you that having a Badlands, a Plateau, and a Scrubland be the only white-bordered cards in my Kaalia deck grates at me a little.
I know a gentleman who has a set of 100 Beta lands for when he drafts. I'm very jealous. Even when his draft deck loses, it's still pimp.
Foreign Printings
Magic has been printed in a couple of dozen different languages. It's a lot of fun to have foreign-language cards, as long as you know what they do. For me and my friends, foreign cards are fun to say out loud, too. A German Lightning Bolt is a Blitzschlag or my Italian foil Kokusho is Kokusho, la Stella della Sera and it's just a good time!
Depending on where you are, some languages are more common. It's been my experience that here on the West Coast, Japanese packs are more common, whereas on my trips to the East Coast, European languages were easier to find in packs.
The first major translations were during Revised, and that's where dual lands were last seen. So you can find foreign-language, black-bordered dual lands (often called FBB duals) and they have the same nesting-rectangle look as the originals.
Wizards doesn't do many special editions in foreign languages. Judge foils and event promos are only in English, neither are the From the Vaults cards, at least not yet. Duel Decks have been in other languages, as have Planechase and the preconstructed Commander decks. As Magic's popularity grows in other countries, the editions of foreign printings will probably increase too.
Foreign Foils
This is hot and spicy. Magic is still predominantly printed in English, and the print runs are smaller in other languages. Korean wasn't a printing for a while, but it's back now. Depending on the set, different languages were the smallest printings and it's tough to nail down specifics.
What is known for sure that when there are less cards, the foils and foil rares/mythics are correspondingly harder to find. So when you get a chance to pick up a foreign foil rare, you should at least think about it.
I love foreign foils and trade for them pretty hard when the opportunity comes up. Be warned that price data is not always consistent, since retailers may not have any foil French Akroma, Angel of Fury for sale.
Artist Signings
I'm in favor of this, but opinions vary widely. For a more in-depth explanation, I refer you to my earlier article.
Misprints/Miscuts
It happens far less these days, but there's a lot of glorious screwups in Magic's history. Missing mana costs, incorrect mana costs, the wrong power/toughness, the wrong text, the wrong color, the wrong card back...yeah, all of these have happened. (Thanks to the SQUT page!)
It's also happened where the cards are cut out of the sheet and are out of alignment. Mostly, this results in cards being off-center and no big deal. But there are occasions where you see bits of the card that was nest to it. Eternal-Central has some good stuff on this topic, covered here.
People collect these for the rarity, and the 'wow' aspect. I've never been a big fan myself, but I can see the appeal of having something so unusual.
Custom Alters
What I do with my custom generals can be called an alter, though I usually don't call them that. I don't use the original card. Plus, my method makes for noticeably thicker and stiffer cards, definitely not tournament-legal.
Most alterations are done with markers or paint. I've got more than a few cards that an artist drew something extra on, like my Lurking Predators. Lots of artists, but not all, are willing to draw something on your cards for a nominal fee. This is usually done with a marker, and mostly is a convention/big event happening. If you email an artist, they may take a commission for something when they have more time.
It's not unheard-of for an artist to have a stack of cards they take to the hotel room overnight, to be delivered the next day of the event. Be polite and inquisitive, and take no for an answer. I've seen Terese Nielsen at a couple of events and she doesn't have time for any alters.
The most common alteration done with paint is to paint over the black border of a card. This isn't hard to do, I'm told, because you're just extending what is already present. This sets your colors, shapes, and tone. Some artists will do this fairly cheaply.
More full-scale work will cost progressively more money, culminating in cards where only the name and mana cost are visible. That's one of the keys to keeping a card tournament-legal. (Always ask the head judge of an event if your altered card is legal to use in your deck, and have an unaltered one in case they say no.)
If you have an altered card, get your general done first so you can show it off more. I really like my Lurking Predators, and I find myself being super-impatient about drawing it so that others can see it and have that moment of 'That's pretty awesome!'
I can imagine it would be hard to have something like this Serra Angel by cardkitty and have it as one of the 99. I'd want to hang it on the wall, or cheat it into play every game!
Combinations
Any of the above are awesome. Combining them is a real thing--foreign foils or foreign alters can look outstanding and are truly unique works of art. Again, be sure you can explain the card! I've seen some amazing alters to a Japanese Sensei's Divining Top but the card takes a lot of familiarity.
There are other things you can do to pimp out your deck, like custom sleeves or an amazing deck box, but I've prattled on enough.
If you follow me on Twitter (and if you aren't, you should be!), you know my wife and I just had a baby girl. So while you may be looking forward to a review of the ten guild champions in Dragon's Maze, or the always-too-wordy set review, understand that my updates are about to get sporadic-to-nonexistent for a little while.
I urge you to join up and follow me on Twitter if you want occasional bite-size commentary, especially since we are in the throes of a new set.
Thanks again for reading!