
Quick answer — Sora Amamiya performed 5 anime themes, including "Ano Hi no Mama no Bokura" from KONOSUBA -God's blessing on this wonderful world! 3, "Ouchi ni Kaeritai" from KONOSUBA -God's blessing on this wonderful world! 2, "Eien no Aria" from The Seven Deadly Sins: Dragon's Judgement.
Sora Amamiya performed the anime theme songs "Ano Hi no Mama no Bokura" (KONOSUBA -God's blessing on this wonderful world! 3), "Ouchi ni Kaeritai" (KONOSUBA -God's blessing on this wonderful world! 2), "Eien no Aria" (The Seven Deadly Sins: Dragon's Judgement), "Ningen Come True!" (A Misanthrope Teaches a Class for Demi-Humans), "Regeneration" (The Seven Deadly Sins: Imperial Wrath of the Gods).
Sora Amamiya's first listed anime theme is "Ano Hi no Mama no Bokura", the ending of KONOSUBA -God's blessing on this wonderful world! 3.