Quick answer — Hoshina Anniversary performed 1 anime theme, including "Theme for Panty & Stocking" from Panty & Stocking with Garterbelt.
Hoshina Anniversary performed the anime theme songs "Theme for Panty & Stocking" (Panty & Stocking with Garterbelt).
Hoshina Anniversary's first listed anime theme is "Theme for Panty & Stocking", the opening of Panty & Stocking with Garterbelt.