The Elfball deck is a Green combo deck that became really popular with the Onslaught and Mirrodin blocks. Many of you may remember mana-producing-elves interacting with other elves to produce even more mana, and token-generating-elves providing fodder for Skullclamp: this popular version of the deck was indeed a beast, and inspired many casual players (me included) to build their own version. The modern day Nettle Sentinel + Heritage Druid Elf Combo deck is a heir to this concept.
The truth of the matter, though, is that elves started to become an increasing presence in Green decks since Urza's block, which provided amazing mana producing elves, such as Priest of Titania and Rofellos, Llanowar Emissary. Such elves enabled Green-based tinker decks like Angry Hermit by allowing swift mana ramp. Combined with a tutor system of some sort or a draw engine, they could easily fill the battlefield with more threats than any player could be confortable with. It was with the Onlsaught block, however, that players were pushed in the direction of building a tribal deck, given the many new synergies between creatures of the same type that spawned in that block. Many saw this as detrimental to the game as it provided players with obvious cards synergies, rather that encouraging players to find new ones for themselves. Others found the concept of a tribal deck to be fascinating and amusing, and I suspect that, to many, it still is. I'll let you pick a side.
Now, the deck above is largely inspired on a design by Treesinger, a user on MTG Salvation Forum*. I really liked his concept, as it somewhat exemplify the saying 'the best of two worlds'. You have Urza's elves and Onslaught's elves; lots of mana and card drawing, but no clamp (hideous artifacts!). I must add that this deck, though it could be put in the same basket with the one I depicted above, is not so much a variant of that concept, but rather a 'cousin', so to speak.
This deck embodies Green's Persistency. Seriously, the elves just keep coming. The beauty of it is that these little pests provide everything you need to run this deck: the mana, a draw engine and bodies to throw at your opponent. With 12 1CMC and 8 2CMC mana dorks this deck can easily run as low as 18 Forests. In addition, the deck features many ways of drawing cards, besides the two main draw engines: Sylvan Messenger and Brass Herald. In a deck that features 42 creatures, almost entirely elves, you are always sure to be drawing 2-3 elves with every Messenger or Herald played. It is not unusual to restock your hand entirely. Bloodline Shaman lets you rather consistently draw an additional elf every turn. Occasional drawing is provided by Gempalm Strider's and Heart Warden's cycling abilities.
My favourite card in this deck is Llanowar Sentinel: like Squadron Hawk, it's like a little army all in one card. The difference is that the body is more beefy (2/3) and the reinforces are put directly into play for a discounted cost. Both Brass Herald and Gempalm Strider pump your ranks, the last one being a small sized Overrun, and yet nothing to laugh at. If everything goes according to plan, sheer numbers and a little strenght boost will give you victory, sometimes in a single blow.
As for the weaknesses: creature removal is a traditional weak spot for elves decks and mass removal is especially dangerous. However, this deck's strenght is that it provides lots of opportunities to repeat your strategy, if you are hindered. As for mass removal: the obvious advice would be to avoid over-extending, however it may be argued that this deck actually rewards you for casting as many creatures as possible. Between Brass Heralds and Sylvan Messengers you'll keep restocking your hand. Having a board filled with elves usually means you're drawing a lot of cards too: just be sure to keep a bunch of elves in your hand as a backup.
On a side note, the original design of this deck featured Fyndhorn Elves and Quirion Ranger in place of Elves of Deep Shadow and Birchlore Rangers. For those not familiar with my deck designs, I try to build decks only with cards that I own, and I don't like to swap creatures from a deck to another: for this reason, while Fyndhorn Elves would be the best choice for this deck, I preferred to give Elves of Deep Shadow some love and a spotlight (they are gorgeous). That being said, if I had some spared Fyndhorn Elves, I would have used them. As for the Birchlore Rangers: they are really doing a great Quirion Ranger impression in this deck. They can't completely replace them, but they accelerate the deck significantly. What I really like about them (and their cousin, Heritage Druid) is that they turn each of your creature into a potential threat. Not in and of itself, but in a deck that makes every bit of mana into a drawing opportunity, every creature that produces mana is a threat to your opponent. As soon as you play a Birchlore Rangers, depending on how many elves you have in play, you may get (instant speed) the exact mana boost you need to put yourself in a significant advantage position. Even if your opponent snipes it as soon as it comes into play, the elf has already fullfilled his duty, as mana abilities are faster than anything. I crave for drawing this elf as much as I do for a Priest of Titania, if not more. No kidding.
*Credits for this deck go to Treesinger:
http://www.mtgsalvation.com/forums/magic-fundamentals/magic-general/334900-casual-elfball
