The twenty-four forms are (1) Vasudeva, (2) Sankarsana, (3) Pradyumna, (4) Aniruddha, (5) Kesava, (6) Narayana, (7) Madhava, (8) Govinda, (9) Visnu, (10) Madhusudana, (11) Trivikrama, (12) Vamana, (13) Sridhara, (14) Hrsikesa, (15) Padmanabha

Expressions researched:
"The twenty-four forms are (1) Vāsudeva, (2) Saṅkarṣaṇa, (3) Pradyumna, (4) Aniruddha, (5) Keśava, (6) Nārāyaṇa, (7) Mādhava, (8) Govinda, (9) Viṣṇu, (10) Madhusūdana, (11) Trivikrama, (12) Vāmana, (13) Śrīdhara, (14) Hṛṣīkeśa, (15) Padmanābha"

Sri Caitanya-caritamrta

CC Madhya-lila

The twenty-four forms are (1) Vāsudeva, (2) Saṅkarṣaṇa, (3) Pradyumna, (4) Aniruddha, (5) Keśava, (6) Nārāyaṇa, (7) Mādhava, (8) Govinda, (9) Viṣṇu, (10) Madhusūdana, (11) Trivikrama, (12) Vāmana, (13) Śrīdhara, (14) Hṛṣīkeśa, (15) Padmanābha, (16) Dāmodara, (17) Puruṣottama, (18) Acyuta, (19) Nṛsiṁha, (20) Janārdana, (21) Hari, (22) Kṛṣṇa, (23) Adhokṣaja and (24) Upendra.

CC Madhya 20.223, Translation and Purport

“According to the Siddhārtha-saṁhitā there are twenty-four forms of Lord Viṣṇu. First I shall describe, according to the opinion of that book, the location of the weapons, beginning with the disc.

The twenty-four forms are (1) Vāsudeva, (2) Saṅkarṣaṇa, (3) Pradyumna, (4) Aniruddha, (5) Keśava, (6) Nārāyaṇa, (7) Mādhava, (8) Govinda, (9) Viṣṇu, (10) Madhusūdana, (11) Trivikrama, (12) Vāmana, (13) Śrīdhara, (14) Hṛṣīkeśa, (15) Padmanābha, (16) Dāmodara, (17) Puruṣottama, (18) Acyuta, (19) Nṛsiṁha, (20) Janārdana, (21) Hari, (22) Kṛṣṇa, (23) Adhokṣaja and (24) Upendra.