Mono-Black Aggro curves out fast with cheap creatures like Forsaken Miner and Iridescent Vinelasher, so you need to trade efficiently and race; Mossborn Hydra's trample lets it push damage through blockers while growing quickly off landfall, and Surrak's trample plus 3 toughness makes it a solid blocker and clock. Esper Origins does nothing on the turn it's cast defensively and is too slow against this aggressive curve, while Mole Man's fragile 1/1 tokens trade poorly into their bigger threats like Nighthowl Pursuer with ferocious. Keep Meltstrider's Resolve in since it's efficient removal against their many small creatures, effectively killing most of their early plays via the fight ability while adding toughness to your blocker.