Most power mantra in Jain
In Jainism, the most revered and widely regarded powerful mantra is the Navkar Mantra (also called Namokar Mantra). It is the universal prayer that venerates the Arihants, Siddhas, Acharyas, Upadhyayas, and Sadhu-s. It is recited at the beginning of most Jain prayers and rituals, and it is considered a concise, potent remembrance of the paths and perfection of liberated beings.
Notes:
- There are small differences in how Digambar and Shwetambar traditions recite and order certain lines, but the essence remains the same: paying obeisance to the first five venerable categories.
- If you’d like, I can provide the exact text in the Digambar and Shwetambar versions and explain their meanings (arth) from authentic Jain sources.