Magnetic refrigeration based on the magnetocaloric effect (MCE) of magnetic solids has been considered as an emerging technology for hydrogen liquefaction. However, the lack of high-performance materials has slowed the development of any practical applications. Here, we present a family of rare-earth cobalt nickel-based magnetocaloric materials, namely Dy1-xHoxCoNi and Ho1-xErxCoNi compounds, and systematically investigated their structural and magnetic properties as well as the MCE and magnetocaloric performance. All of these compounds crystallize in the C15-type Laves-phase structure and undergo typical second-order magnetic phase transition (MPT). The change in magnetism and the MPT temperature for the Dy1-xHoxCoNi and Ho1-xErxCoNi compounds originate from the exchange interactions between nearest-neighbor RE3+ ion pairs. No hysteresis magnetocaloric effect was achieved, and the MPT temperature of these compounds could be tuned from the liquefaction temperature of nitrogen (∼77 K) to hydrogen (∼20 K) by adjusting the ratio of rare-earth elements. This study's findings indicate that the Dy1-xHoxCoNi and Ho1-xErxCoNi compounds are of potential for practical magnetic refrigeration applications in the field of hydrogen liquefaction.