Are all discovered normal distribution in the physical world a result of central limit theorem?

There are several ways to motivate measurement errors being Gaussian (Jaynes has a whole chapter on them, summarised here).

Normal distributions are found elsewhere too. jacob1729 noted one example of a Normal distribution resulting (in thermal equilibrium) from a quadratic energy, a very important scenario. Another interesting example is a quantum SHO's ground state, which is Normal in either $x$ or $p$-space; the reason is we have to solve $\hat{a}|\psi\rangle=0$.

The $x$ component of the velocity of an ideal gas is normally distributed for entirely different reasons, so no.