Including #1: Tyvar, Jubilant Brawler Despite not being an elf on his type line, I will consider Tyvar, Jubilant Brawler a second elf on this list
Despite being a mono-green list, Delighted Halfling and Birds of Paradise are still making the cut simply on the off-chance that your opponent's cast a spell that requires you to have differently-colored mana, and they're both at least as good as the Llanowar / Fyndhorn / Elvish Mystic trio
To pick the right card sleeves, focus on the size, durability, and design that fit your style and keep your cards safe during play
A three-mana combat trick is a big ask, but this will make a huge difference in a race, and because it cantrips, is going to slot nicely into the UB draw-two archetype.