Speaking of Rādhā, we cannot leave out her śaktimān — Kṛṣṇa. As you know, a number of Tantras correlate Kṛṣṇa with Kālī, who is manifested through him. However, Tantras are an immense ocean of the most diverse possibilities, multidimensional perception of apparently one and the same phenomenon. So for example, according to the Tantra-rāja-tantra (34/11), the Goddess Lalitā Tripurasundarī is also manifested through Kṛṣṇa:
कदाचिदाद्या ललिता पुंरूपा कृष्णविग्रहा |
kadācidādyā lalitā puṃrūpā kṛṣṇavigrahā |
Sometimes (kadācit) the primordial (ādyā) Lalitā appears in the masculine form of Kṛṣṇa (puṃrūpā kṛṣṇavigrahā).
It may seem contradictory for those, who are used to dividing the worshipping of Lalitā and Kālī in a strict way, but Kālī could also be a part of Śrīkula. When through Śrīkula you obtain the experience of fullness, you come to the liberation from limitations of time, for which Kālī is responsible. Therefore, she is also inseparable from Tripurasundarī. We can say that Kāmakalā Kālī (the highest form of Kālī), worshiped in Urdhvāmnāya (of Kālī–kula krama), is most strongly associated with Tripura. Or, we can consider Tripurasundarī itself as Rakta Kālī (Red Kālī). Thus, we can see one reality from different perspectives.
The unity of Śrī and Kālī-kula is revealed in the story described in the kaula text the Rādhā Tantra. In short, it describes a long story of how Viṣṇu with the blessings of Tripurasundarī is embodied in the form of Kṛṣṇa, and Lakṣmī in the form of Rādhārānī (in fact, she herself is considered as a manifestation of Tripurasundarī). They both worshiped Kālī and also Kāmākhya, where Kṛṣṇa invokes Kālī into the Rādhā’s body. The first part of the Rādhā-tanra describes the famous mantra of Lalitā Pancadaśī, it also speaks of Ten Mahāvidyās, of which Tripurasundarī is the main one (tasmād daśasu vidyāsu pradhānaṃ tripurā parā). These Mahāvidyās are worshiped in a special way in Śrīyantra by experienced practitioners. The Rādhā Tantra speaks of her as giving realisation of the four puruṣarthas (dharmārthakāmamokṣadāyinī), and because of her worship in kaula-sādhana, Kṛṣṇa realised all siddhis. We know many stories about the successes of Kṛṣṇa, and all His siddhis, according to the Rādhā Tantra, were achieved through this upāsana. The text also frequently mentions the term ‘yoga’ in relation to tantric sādhana; in the second part of the RT (ślokas 3-4), the union of Kṛṣṇa and Śakti (Rādhā) is called Śakti Yoga. The famous Hare Kṛṣṇa maha-mantra can also be found in there. There is also a description of the preliminary practice of purification (karṇa-shuddhi), the ability to purely hear the tantric mantras of Mahāvidyā. Periodically, recommendations for contemplating sacred places in one’s own body are given there (Ch. 5, ślokas 11-12 or Ch. 14, ślokas 1-2), for example, Govardhan Hill in sahasrāra–cakra, etc. It also refers to the kula-kuṇḍalinī awakening through yoni-mudrā (Ch. 15 / 19-21). Apparently, the text speaks of yoni-mudrā as the body of the Goddess, rather than the technical practice of haṭha-yoga in the likeness of ‘ṣaṇmukhi–mudrā’. Although, for a long time, it is no secret that the essential elements of tantra are also connected with many practices of the well-known and popular haṭha–yoga, the essence of which is currently understood by a very small number from millions of practitioners.
From my point of view, Gaudiya Vaiṣṇavism was once influenced exactly by vāmācāra, but in a Vaiṣṇava Śakti format. In the course of time, most likely, everything came down to formal substitutions (anukalpa) and symbolism, so the doctrine became more refined.
Today is the Rādhāṣṭamī festival associated with Śrī Rādhika, Śakti of Kṛṣṇa.
My congratulations and blessings to everyone. Jay Śrī Rādhe!