To reduce the synthesis pressure while preserving relatively high critical temperatures is an important issue in the study of superconducting hydrides. Here we report our efforts along this direction in lanthanum-cerium and yttrium-cerium alloy hydrides. The chemical pre-compression was created by partially substituting La with Ce and Y with Ce, respectively. The synthesized phases, stoichiometric compositions, and structures were characterized using X-ray diffraction and Raman spectroscopy measurements with combined theoretical calculations. The superconducting transition temperatures of 100-180 K in two ternary hydrides from the resistivity measurements were obtained at the almost half pressure level as needed for near-room temperature superconductor LaH₁₀. The obtained superconducting parameters indicate the short-range pairing of superconductivity and the possible BCS-BEC crossover in the studied hydrides. We also discovered superconductivity at 40 K in Zr-N hydrides, the transition metal – nonmetal hydrides. These results and discoveries reveal rich physics in superconducting hydrides.