Fluorescent emitters in diamond are considered to be a valuable resource for fields such as quantum communication, quantum photonics, and biological imaging. In this paper, we report a wide range of narrow bandwidth ( ~ 1.5 nm) spectral emission lines arising from different color centers at room temperature. The defects were created by chemical vapor deposition of thin diamond films grown on silica substrates seeded with nanoparticles of diamond and nickel. These fluorescent lines also possess single or few centers photon statistics. We correlate the zero-phonon lines, observed using confocal microscopy, with previously identified nickel-related centers which have been observed in high-pressure high-temperature diamond, with a Si/Ni complex and silicon vacancy defects. We compare our findings with recent results demonstrating single-photon emission in diamond associated with nickel-related centers to clarify and summarize previous studies concerning this specific dopant. The great variety of emission lines observed in the synthesized material, mainly associated with nickel-related centers, could be an important resource for applications relying on the presence of several emitters of single photons in the same sample. Moreover, the possibility of mass production of these centers in nanodiamonds in colloidal suspension may provide an important resource for biomarking and microscopy.