Devotees of Lord Krishna-Who are the Bonafide Sampradias in pure a disciplic succession?

Answer 1

In order to understand the tattva-siddhanta or conclusive reality, and actual teachingsof the entire Bhagavad-Gita from its auspicious beginning to its final conclusion, it is necessary to first of all become fully surrendered to one of the four authentic and bonafide spiritual channels of disciplic succession in one of the four empowered sampradayas as revealed in the Vedic scripture Garga Samhita given earlier in this forward. This is the only means for us to be recepients of the pure vani or spiritual knowledge which is free from the four defects which is revealed by the nitya-siddhas who are eternally omniscient personalities, far beyond the mundane realm of the material existence.

There are four Vaishnava sampradayas according to Padma Purana quoted in Böthlingk Sanskrit-Sanskrit dictionary, entry Sampradaya, Sabda-Kalpa-Druma Sanskrit-Sanskrit dictionary and Prameya-ratnavali 1.5-6 by Baladeva Vidyabhushana:

sampradaya vihina ye mantras te nisphala matah
atah kalau bhavisyanti catvarah sampradayinah
sri-brahma-rudra-sanaka vaisnavah ksiti-pavanah
catvaras te kalau bhavya hy utkale purusottamat
ramanujam sri svicakre madhvacaryam caturmukhah
sri visnusvaminam rudro nimbadityam catuhsanah

"Unless one is initiated by a bona-fide spiritual master in the disciplic succession, the mantra he might have received is without any effect. For this reason four Vaisnava disciplic successions, inaugurated by Sri, Lord Brahma, Lord Rudra, and Sanaka (one of the four Kumaras), will appear in the holy place of Jaganatha Puri, and purify the entire earth during the Kali yuga (current age). Sri chose Ramanuja to represent her disciplic succession. In the same way Lord Brahma chose Madhvacharya, Lord Rudra chose Visnu Svami, and the four Kumaras chose Nimbaditya (Nimbarka)."

One example of a Vaishnava parampara is the Brahma Madhva Gaudiya Vaisnava Sampradaya.-

Answer 2

the Ramanuja-sampradaya, the Madhva-sampradaya, the Visnusvami-sampradaya and the Nimbarka-sampradaya.

The Madhva-Gaudiya-sampradaya in particular comes from Lord Caitanya Mahaprabhu. All these devotees are spreading this Krsna consciousness movement very widely and giving protection to innocent people who are being so much embarrassed by pseudo-avataras, -svamis, -yogis and others.