Abomination of Llanowar - The Elvish Swarm
About the Deck
I've tried to stick to the concept of as few non-elf, non-land cards as possible since every non-elf, non-land is less power for the mighty elvish swarm. I would prefer to keep the deck at least 50% creatures.
This deck simultaneously goes wide and threatens kills by commander damage, which can allow you to put some significant pressure on your opponents. The Abomination of Llanowar gets big really quick, it isn't uncommon to swing for 4+ commander damage on Turn 3 if your dropped a mana-elf on turn 1, and it gets much scarier every turn after that usually.
The deck is actually pretty resilient to board wipes as they don't really affect the commander's damage output for the most part, unless it is mass exile. Following up a board wipe by replaying Abomination of Llanowar if you have Concordant Crossroads in hand or in play, can unexpectedly kill people, but even without haste, you've got good odds if you have to wait a turn cycle after a wipe since the commander has built in evasion due to menace.
Very often you will be killing players via the combat step. However, Shaman of the Pack, Skemfar Shadowsage, Lathril, Blade of the Elves, as well as using Jarad, Golgari Lich Lord to sacrifice Abomination of Llanowar, can be great ways to deal damage outside of combat, and may be needed if facing Fog effects.
Cards For Future Consideration
Entomb, Buried Alive - Being able to put Jarad, Golgari Lich Lord or Elvish Dreadlord directly into the graveyard seems worthwhile. These also work as pump spells for Abomination of Llanowar. These have synergy with Volrath's Stronghold, Phyrexian Reclamation and Patriarch's Bidding as well.
Living Death - This seems extremely good as a redundancy for Patriarch's Bidding but I just haven't found the space.
Filth - This is not an elf, but the evasion potential is huge since it is rare to not see a black deck on the table, and I am running Urborg, Tomb of Yawgmoth. However, since I am not running any real discard outlets or cards like Entomb, getting it into the graveyard might requiring playing it and having it die, which I think may be too slow. I may experiment with Entomb and/or Buried Alive in the future, and if so then this card may make the cut.
Morality Shift - This would in theory make the commander lethal instantly and combos with Patriarch's Bidding well. If I were including the usual black tutors then setting up something like Concordant Crossroads + Morality Shift + Patriarch's Bidding would probably be a viable thing to try and pull off. This might be a little too goofy to try pulling off, I don't know if I'll actually try it.
Crop Rotation - This is 100% worth including and I'm sure I could find room for it, but for now I want the non-land, non-elf cards to really be kept to a minimum. This likely will be added eventually as being able to more reliably get Volrath's Stronghold, Gaea's Cradle or any other utility land would be great.
Budget Options
The only somewhat pricey cards I would say are "must haves" are the cheaper mana cost mana dorks like Heritage Druid and Priest of Titania. I probably wouldn't want to run a lower budget version of the deck without those two unless absolutely necessary since they do truly make the deck explode quickly.