In Jainism, there are exactly 24 Tirthankaras. There is no officially recognized “endless” or infinite Tirthankar. Each Tirthankar is a distinguished liberated soul who revives the Jain path in a given time, teaches right conduct, and then leaves the world when his mission is complete. After him another Tirthankar appears in the cycle of time, until the 24th (Mahavira) who is the last to appear in this cosmic cycle.

If you meant something like:

• Anadi (beginningless) Tirthankar: some discussions in Jain literature use the term “anadi” to refer to the infinite cycle of time and the eternal nature of the Jina ideal, but this does not mean there is an actual endless series of Tirthankaras within a single era. In standard Jain teaching, the 24 Tirthankaras are finite and fixed in number, each appearing in different eras.
• A general, timeless guide: any Tirthankar (or the Jina as a spiritual guide) represents the perpetual ideal of liberation for beings in that era.

For clarity, the 24 Tirthankaras, in order, are: Rishabhanatha (Adinath), Ajitanatha, Sambhavanatha, Abhinandananatha, Sumatinatha, Padmaprabha, Suparshvanatha, Chandraprabha, Suvidhinatha, Shitalakshka, Shreyamsa, Vasupujya, Vimalanatha, Anantanatha, Dharmanatha, Shantinatha, Kunthunatha, Aranatha, Mallinath, Munisuvrat, Naminath, Neminath, Parshvanath, Parshva, and Mahavira.

If you were aiming for a specific name or a particular interpretation (Digambar vs. Shwetambar nuance), tell me exactly what you have in mind and I’ll explain that aspect accordingly.