The discovery and design of new qubits forms the foundation of many of the technologies and grand challenges in quantum information science. New materials, novel quantum phases, and new qubit designs can mitigate noise and loss that plague current quantum processors. The development of new qubits and qubit architectures enables fundamentally new opportunities in error correction and scaling. Quantum networks require the discovery of new qubits that satisfy the demanding technical requirements of entanglement distribution. New opportunities and applications in sensing, metrology, and imaging could be enabled by the discovery of new quantum sensors. On-going work to identify new qubits and engineer their host materials is critical to realizing new quantum applications. This enterprise is highly interdisciplinary, with diverse subfields spanning materials science, optics and photonics, microwave engineering and circuit design, and atomic physics and spectroscopy.