3D printing is a technology suitable for creating electronics and electromagnetic devices. However, the manufacturing of both dielectric and conductive parts in the same process still remain a challenging task. This study explores the combination of 3D printing with traditional manufacturing techniques for antenna design and fabrication, giving the designer the advantage of using the additive manufacturing technology only to implement the most critical parts of a certain structure, ensuring a satisfying electromagnetic performance, but limiting the production cost and complexity. In the former part of the study, the focus is on three proximity-coupled patch antennas. It demonstrates how hybrid devices made of metal, dielectric, and 3D-printed (using Fused Filament Fabrication) conductive polymers can be successfully simulated and created for different operating frequency bands. In the latter part, the study compares three prototypes of a 5G-NR, high gain, and wideband waveguide antenna: respectively a fully 3D printed one made of electrifi (which is the most conductive commercial 3D-printable filament), an all-metal one, and a hybrid (3D-printed electrifi & metal) one. The results show a 15% reduction in efficiency when using the all-Electrifi configuration compared to all-metal one, and a 4-5% reduction when using the hybrid version.