In China, the “orthodox” vocal liturgy of both Buddhist and Daoist temples has been thought to be properly accompanied only by ritual percussion (see e.g. here, and here)—just as in Islam and Christianity.
Although many temple and household ritual groups further incorporate melodic instrumental ensemble, the core practice among household ritual specialists is vocal liturgy with percussion.
For the Li family Daoists in north Shanxi, see my film, and e.g. The Invitation ritual, Pacing the Void 2, and audio tracks ##1–3 on the playlist (in the sidebar, with commentary here). Other instances of vocal liturgy with percussion include the Daoists of Changwu (Shaanxi), the performance of “precious scrolls” in Hebei (playlist #7), as well as ritual groups in Jiangsu and all around south China. So in order to understand religious practice in China, we must take into account how ritual texts are performed—through singing.
Further west, note Byzantine and Gregorian chant cultures, and examples from Eritrea and Athos. Around the world, a cappella singing (both liturgical and secular) is perhaps the dominant means of expression; see e.g. Sardinia, and Albania.
Even more minimally, dispensing with percussion, a cappella singing is a notable feature of religious-inspired WAM —some instances:
Some of these were composed for church services (and I haven’t even begun to broach the riches of Bach motets…); but as we move through the 19th century, pieces also began to be written for the quasi-secular setting of the concert stage.