Quick answer — Nagi Yanagi performed 5 anime themes, including "Aqua Terrarium" from A Lull in the Sea, "My Teen Romantic Comedy SNAFU - Opening | Yukitoki" from My Teen Romantic Comedy SNAFU, "My Teen Romantic Comedy SNAFU Climax! - Opening | Megumi no Ame" from My Teen Romantic Comedy SNAFU Climax!.
Nagi Yanagi performed the anime theme songs "Aqua Terrarium" (A Lull in the Sea), "My Teen Romantic Comedy SNAFU - Opening | Yukitoki" (My Teen Romantic Comedy SNAFU), "My Teen Romantic Comedy SNAFU Climax! - Opening | Megumi no Ame" (My Teen Romantic Comedy SNAFU Climax!), "My Teen Romantic Comedy SNAFU TOO! - Opening | Harumodoki" (My Teen Romantic Comedy SNAFU TOO!), "Natsu no Sumika" (Turkey! Time to Strike).
Nagi Yanagi's first listed anime theme is "Aqua Terrarium", the ending of A Lull in the Sea.
