if I will step-by-step add the parallel resistors, the total current will grow?
Yes, by adding resistances will parallel the effective resistance is going to decrease.
the effective resistance of a parallel circuit is always less than the least resistance in that network.
even there only 1V, the value of current can be over 10 50 100 or more A?
Yes, if the power supply is capable enough and the resistors also to be able to dissipate that power.
And hence, even an 1V voltage source can melt a wire?
Yes, current is the one responsible for melting and voltage is the driving force for current.
or create strong magnetic field?
yes it will.