Is there a component/method that can take any signal, then increase it to 5 volts no matter how small the signal is?
It's called a comparator, which is basically an op-amp optimized to provide as much gain as possible under all circumstances; So much gain that it provides maximum or minimum output and hits its power rail.

Use a reference input of 100mV on the inverting input and apply your signal to the non-inverting input.

In other words, it just outputs a HI when the voltage of one input terminal is higher than the other, and outputs a LO otherwise.