As mentioned above, balancing the right number of cards in each of the categories below has been tough to get right. I'd love to hear from other Hallar players about how you've achieved it - and any suggestions you have for cards I'm missing.
Ramp
Having plenty of ramp sources is vitally important for this deck. Most of our kicker spells are quite mana intensive and it's likely that
Hallar, the Firefletcher willl be removed at least once during the game so we need plenty of mana to recast him. Right now we're running
Jeska's Will,
Rampant Growth,
Nature's Lore,
Farseek,
Sakura-Tribe Elder,
Primal Growth,
Llanowar Elves,
Elvish Mystic,
Fyndhorn Elves,
Goblin Anarchomancer,
Kami of Whispered Hopes and
Exploration, along with the ubiquitous
Sol Ring. The goal is to have at least one ramp source in your opening hand.
+1/+1 Counters
We want to put enough +1/+1 counters on
Hallar, the Firefletcher or
Giggling Skitterspike in as efficient a way as possible, to turn them into a game-ending threat. Cards chosen for this purpose are
Forgotten Ancient,
Ozolith, the Shattered Spire,
Halana and Alena, Partners,
Immaculate Magistrate,
Pir, Imaginative Rascal,
Verdurous Gearhulk,
Vorinclex, Monstrous Raider,
Increasing Savagery,
Inscription of Abundance,
Solidarity of Heroes,
Blade of the Bloodchief,
Kami of Whispered Hopes,
Branching Evolution,
Doubling Season,
Evolutionary Escalation,
Hardened Scales and
Retreat to Kazandu. It doesn't generate +1/+1 counters itself but
The Ozolith is a staple for this deck.
Protection
We need to protect
Hallar, the Firefletcher at all costs as opponents will target him. We run a couple of different ways of keeping him alive: either one-shot instants; or multi-use permanents. Cards in the former category are
Heroic Intervention,
Inspiring Call,
Vines of Vastwood,
Gaea's Gift,
Snakeskin Veil and
Wrap in Vigor (I might also add
Deflecting Swat to that list if I can find room for it). Our multi-use permanents are
Darksteel Plate,
Lightning Greaves,
Mask of Avacyn,
Mithril Coat,
Swiftfoot Boots and
Whispersilk Cloak. As with our ramp sources, ideally we want to see at least one protective card in our opening hand.
Kicker Cards
Our kicker cards are chosen to be as mana efficient as possible. Ideally we're looking for a maximum total mana value of
for their combined casting cost and kicker cost. If they have relevant or impactful effects then all the better, but efficiency is the priority here. We also want to run enough of them that we can reliably draw into them to power
Hallar, the Firefletcher. At the moment we're running 12 cards with a kicker ability:
Flametongue Yearling,
Breath of Darigaaz,
Untamed Kavu,
Verduran Emissary,
Vines of Vastwood,
Grow from the Ashes,
Primal Growth,
Reclaim the Wastes,
Comet Storm,
Gift of Growth,
Inscription of Abundance and
Everflowing Chalice. Whether these are enough is something to be evaluated.
Card Draw/Tutors
This is where most of the recent development of this deck has been focused. We run
Beast Whisperer,
Inspiring Call,
Stocking the Pantry,
War Room and
Bonders' Enclave as sources of card draw and I'm also planning to add
Sylvan Library soon.
Jeska's Will also acts as pseudo-card draw.
Worldly Tutor,
Imperial Recruiter and
Archdruid's Charm are our tutor cards to find
Giggling Skitterspike as our plan B Commander if
Hallar, the Firefletcher is removed.
Removal
Gruul isn't the strongest colour combination for destroying permanents as it tends to try and remove players instead.
Beast Within,
Chaos Warp and
Wild Magic Surge are our most versatile options, plus we're running
Atraxa's Fall,
Boseiju, Who Endures,
Decimate,
Verduran Emissary and
Zoyowa's Justice to take care of specific card types.
Breath of Darigaaz is a kicker card that also comes about as close to a boardwipe as we have (along with
Chandra's Ignition).
Other Payoffs
We run a couple of other miscellaneous cards, mainly as game-ending finishers to augment
Hallar, the Firefletcher or
Giggling Skitterspike's abilities.
Grafted Exoskeleton is amazing because it turns their damage into poison counters, therefore only needing to deal 10 to each player.
Chandra's Ignition can also be explosive and will effectively trigger twice if we're using it on
Giggling Skitterspike.