Reactive oxygen species (ROS) are unstable molecules that constantly threaten the genomic integrity of all domains of life, including bacteriophages. Since ROS can react with nucleic acid, proteins, and lipids, causing permanent damage in a cell, all organisms have evolved protective mechanisms against ROS. These mechanisms range from scavenging toxic radicals to repairing the genome when damaged. Previous findings from our laboratory revealed functional phage-encoded ROS scavengers in uncultured bacteriophage genomes. Thus, environmental bacteriophages are good sources for discovering novel genes involved in protecting against ROS. We subsequently constructed five functional DNA libraries (genomic, multigenomic, and three metagenomic) using various sources of DNA recovered from the environment and cultured bacteriophages. We named these Inducible Multi Metagenmic RecombinanT Libraries (IMMRTL) v.1.0, which can be valuable resources for discovering novel biology. Then, we screened IMM*RTL v.1.0 in mutant E. coli lacking all major ROS scavengers (Δcatalases) for their ability to rescue bacterial mutants from a fatal oxygen radical challenge. Here, we report the overall DNA library construction, the screening process, and the recovery of positive hits that overcame both fatal ROS attacks and genetic defects. These hits may help elucidate novel mechanisms that bacteriophages possess to guard their nucleic acids against ROS and may help shed some light on preventing ROS-associated diseases such as aging and cancer.