Designing and synthesizing novel, low-dimensional carbon allotropes, as well as elucidating the inherent correlations between carbon network topologies and their physical properties, remains a core research focus in materials science. This study presents an effective strategy for constructing novel two-dimensional (2D) carbon networks from known carbon allotropes. A series of bubble-like carbon nanostructures composed of 3-, 4-, and 6-membered rings has been theoretically proposed, which are suitable for embedding into sp²-hybridized 2D carbon frameworks. By integrating these carbon nanostructures into three typical planar 2D carbon allotropes, i.e., trigraphene, T-graphene, and graphene, distinct buckled networks with mixed sp²-sp³ hybridization are obtained. The robust structural stability of these bubble-decorated 2D networks is verified through cohesive energy calculations, elastic constant assessments, and phonon dispersion analyses. Computational results demonstrate that the incorporation of bubble-like structures substantially alters the intrinsic physical properties of carbon allotropes. Metallic or semiconducting behaviors, as well as flat-band characteristics, emerge in these bubble-decorated carbon networks, enabling strong absorption in the visible and ultraviolet spectra. Notably, the bubble-decorated carbon network exhibits enhanced mechanical strength and outperforms graphene. Meanwhile, the introduction of bubble structures significantly suppresses the lattice thermal conductivity of carbon networks, providing an effective route to modulate thermal transport properties via the arrangement of carbon bubbles. This study enriches the family of 2D carbon allotropes and lays a material foundation for the design and fabrication of next-generation all- carbon nanodevices.