Over the past five decades, new discoveries on RNA molecules have expanded the scope of their functionalities beyond information-carrying to include catalysis and regulation of gene expression. Yet much remains to be discovered and understood about functional RNAs. Due to the versatility of these molecules, the synthetic biology field has also shown a growing interest in functional RNAs. The studies presented herein are about small functional RNAs and focus on three different areas: in vitro selections, self–cleaving ribozymes, and riboswitches. First, I present studies that provide insights into improving in vitro selections by enhancing the phenotypic potential of RNA libraries used in the discovery of functional RNAs. The second focus of my studies is the characterization of self-cleaving ribozymes, and I report the first example of allosteric modulation of a natural self-cleaving ribozyme by a metabolite. I also present two different methodologies that can be used in the analysis of self-cleaving ribozymes. Lastly, I present work contributed towards the discovery and characterization of a novel synthetic photoriboswitch, an optogenetic tool that is able to control the downstream mRNA translation with temporal control.