Contrary to belief, Grunts are actually fairly strong, able to:
- Carry and wield a Fuel Rod Gun
- Carry and Wield a Brute Spiker or Plasma Rifle
- Carry, mount and deploy a Plasma Turret
- Ripped apart a human Private Osmo limb from limb in Halo: Contact Harvest
Jackals and by definition also Skirmishers can carry and wield some of the potentially heavier weapons, such as the Carbine, Needle Rifle, Beam Rifle and Plasma Rifle. I'd imagine they'd be about the equal of a Human in combat, possibly stronger, as they do prey upon lesser species such as Humans and Grunts. Skirmishers are probably also pretty strong.
Drones can claw a human to death, or even bodily lift an armored Marine into the air, although this may be with the aid of their antigravity propulsion aided flight.
Elites and Brutes carry some of the Covenant's heaviest weaponry, and can both equal or even best a Spartan in hand-to-hand combat. Undoubtedly the strongest Covanent races, barring a Mgalekgolo/Hunter.