VASP is a commercial electronic structure software package, often used for atomistic simulations. As such, it competes with LAMMPS for certain types of materials simulations, though they operate on different levels of theory and timescales.

GROMACS is a molecular dynamics package primarily focused on biomolecular systems. It competes with LAMMPS in the broader molecular dynamics simulation space, particularly for biological systems.

Quantum Espresso is a suite for electronic structure calculations based on density functional theory (DFT). It competes with LAMMPS (which can use Quantum Espresso to provide potential energy and forces) for some atomistic simulation applications, especially when high accuracy is needed. More generally, Quantum Espresso focuses on electronic structure, while LAMMPS is for dynamics