If you prefer downloading the raw APK file rather than using the Play Store, these sites are common repositories: Hiya: Spam Blocker & Caller ID - Apps on Google Play

: One of the most popular apps for identifying unknown callers and blocking unwanted spam.

: A free and open-source option available on F-Droid. Third-Party APK Repositories

: A comprehensive solution for Hiya that uses a massive database to identify and block spam.