Izzet Spellementals relies on a heavy nonbasic manabase (Riverpyre Verge, Spirebluff Canal, Steam Vents) so Sunspine Lynx's ETB damage trigger punishes their mana base directly. Their big payoffs, Hearth Elemental (a 4/5) and Eddymurk Crab (a 5/5), only get cheaper to cast and never change size. Burst Lightning deals at most 4 damage when kicked and Stingerquill Charm deals 3, so neither kills them on its own. Thought-Stalker Warlock pressures through their lack of early blockers with menace. If they lost life this turn it lets us look at their hand and take a nonland card such as a cantrip or payoff. Otherwise they choose what to discard. Stinging Vitriol is slower, since it only hits the opponent for 2 and takes a nonland card at sorcery speed, and Valley Flamecaller matters less in a race focused on applying early pressure before their engine turns on. Don't spend Burst Lightning or Stingerquill Charm trying to kill Hearth Elemental or Eddymurk Crab. Save burn for smaller creatures and for pushing damage, and race past their large blockers.