This is something I learnt during my die-trying seeking for conversion to Judaism. There is a beauty in Judaism that it does not require you to be Jewish in living a righteous life. Indeed you are always encouraged to be what your Designer wants you to be. Every single human has his or her own purpose in this world. You can reach your full capacity of being good, either you're an Americans, Chinese, Indonesians or Botswanians.
Judaism believe humanity as the son of Noah, who survived the flood catastrophy, are together bound into certain universal codes which serves as the guidance to living righteously, and eventually being saved and inherits the next world (or you may call it heaven or paradise). That is the origin of the term 'Noahides'. Some people never exercise a full conversion to Judaism and opt to be a Noahide.
The Noahidism itself is not a religion per se, it acts more like moral codes that universally bounds us, humanity, no matter what religion we adhere to. These universal codes teach that whatever beliefs you hold to, you can sit down together and agree on these seven basic things: to acknowledge one God as a single God alone and only (my emphasis on monotheism), to respect God, to respect your fellow human being, to respect the properties of others, to respect the sanctification of marriage, to treat every living creatures wisely, and to establish the court of justice. Theoritically you can remain and keep practising your faith while agreeing on these universal codes, however practically you may need to adjust certain aspects of your beliefs, like for example, the idea that no one saves unless believing in the way you do.
Among the existing religions today, Islam and Unitarian Christianity are the most compatible to Noahides. Christians in general might stumble on how they comprehend Trinity. Other religion like Hinduism is somewhat problematic that some people think it is one form of paganism that survives to this date. But this religion may have twice encyclopedic morality laws than yours. While it believes in pantheon of gods, Hinduism acknowledge the idea of one single utmost spiritual Being, although it is abstract and impersonificated. Another Eastern religion that may be problematic is Buddhism. It really does not have near equivalency of how we usually define God. In Buddhism you have Nirvana, the highest reality, but you don't have God. Alternatively, you now have The Buddha, the master, the enlightened one, but after all he's not the God himself. As I am not the expert of this area, I will leave this alone. People interested in Noahides should learn it from Torah scholars, the rabbis, who keep this teaching alive for thousands years.
My journey in seeking conversion seem having ended. I may have hard times explaining people, especially to my children about my religion. But overall, I am happy being a Noahide, keeping a good faith, in the way my Designer wants me to be, that is, being good.
Ari Ben Noah