From Halopedia, the Halo wiki
Naval coilgun (LNT-450 • Mark 55 Castor) • Naval coilgun battery (11A2R1 • Mark 15 Breakwater • Spitfire) • M66 Sentry autocannon • Gauss cannon (M65 • M68 • M68B • M555) • M92 Principle Gauss Cannon • Mini-MAC • "Super" MAC Mass drivers: Onager (Mark 2488 • Mark 2551) • Ballista