A non-Pb piezoelectric ceramic system, Ba(Ti0.8Zr0.2)O3-(Ba0.7Ca0.3)TiO3, exhibits a high piezoelectric coefficient of d33 ~ 620 pC/N at optimal composition. Its phase diagram shows a morphotropic phase boundary (MPB) starting from a tricritical triple point of cubic paraelectric (C), ferroelectric rhombohedral (R), and tetragonal (T) phases. The high piezoelectricity of the MPB compositions is due to the proximity of the MPB to the tricritical triple point, leading to nearly vanishing polarization anisotropy and facilitating polarization rotation between <001>T and <111>R states. The single-crystal form of the MPB composition may reach a giant d33 of 1500-2000 pC/N. This work provides a new recipe for designing highly piezoelectric materials by searching MPBs starting from a TCP. The PZT family has been the icon of piezoelectric materials for half a century. However, due to its Pb toxicity, there is an urgent need for non-Pb substitutes. Non-Pb piezoelectric ceramics generally have inferior piezoelectricity compared to PZT. Recently, their limit has been pushed to a higher level of d33 ~ 300 pC/N, but is still halfway to the most-desired high-end PZT property. The MPB in non-Pb systems exhibits significantly lower piezoelectricity than Pb-based systems. A non-Pb pseudobinary ferroelectric system, BZT-xBCT, was designed. The samples were fabricated using a conventional solid-state reaction method. The phase diagram of this system shows a MPB separating ferroelectric R (BZT side) and T (BCT side) phases. The most important feature of the BZT-BCT system is the existence of a C-R-T triple point at x ~ 32% and T ~ 57°C. The MPB composition 50BCT exhibits anomaly in all of the properties such as the highest spontaneous polarization Pm, highest remnant polarization Pr, lowest coercive field Ec, and highest dielectric permittivity ε. 50BCT shows a high d33 of 560-620 pC/N, which is higher than many soft PZTs. The d33 of 50BCT is about twice that of alkaline-niobate-based ceramics and several times higher than other non-Pb piezoelectrics. The high piezoelectricity of the MPB composition is due to the proximity of the MPB to the tricritical triple point, leading to nearly vanA non-Pb piezoelectric ceramic system, Ba(Ti0.8Zr0.2)O3-(Ba0.7Ca0.3)TiO3, exhibits a high piezoelectric coefficient of d33 ~ 620 pC/N at optimal composition. Its phase diagram shows a morphotropic phase boundary (MPB) starting from a tricritical triple point of cubic paraelectric (C), ferroelectric rhombohedral (R), and tetragonal (T) phases. The high piezoelectricity of the MPB compositions is due to the proximity of the MPB to the tricritical triple point, leading to nearly vanishing polarization anisotropy and facilitating polarization rotation between <001>T and <111>R states. The single-crystal form of the MPB composition may reach a giant d33 of 1500-2000 pC/N. This work provides a new recipe for designing highly piezoelectric materials by searching MPBs starting from a TCP. The PZT family has been the icon of piezoelectric materials for half a century. However, due to its Pb toxicity, there is an urgent need for non-Pb substitutes. Non-Pb piezoelectric ceramics generally have inferior piezoelectricity compared to PZT. Recently, their limit has been pushed to a higher level of d33 ~ 300 pC/N, but is still halfway to the most-desired high-end PZT property. The MPB in non-Pb systems exhibits significantly lower piezoelectricity than Pb-based systems. A non-Pb pseudobinary ferroelectric system, BZT-xBCT, was designed. The samples were fabricated using a conventional solid-state reaction method. The phase diagram of this system shows a MPB separating ferroelectric R (BZT side) and T (BCT side) phases. The most important feature of the BZT-BCT system is the existence of a C-R-T triple point at x ~ 32% and T ~ 57°C. The MPB composition 50BCT exhibits anomaly in all of the properties such as the highest spontaneous polarization Pm, highest remnant polarization Pr, lowest coercive field Ec, and highest dielectric permittivity ε. 50BCT shows a high d33 of 560-620 pC/N, which is higher than many soft PZTs. The d33 of 50BCT is about twice that of alkaline-niobate-based ceramics and several times higher than other non-Pb piezoelectrics. The high piezoelectricity of the MPB composition is due to the proximity of the MPB to the tricritical triple point, leading to nearly van