Hi,
Low power sensors maynot generate much noise.
But the signals of unshielded cables may be influenced by noise signals in the environment.
Mains frequency, inductive or calacjtive coupling of noisy signals nearby, or the wires to the sensor may act like antennas.
In either case decide to use RC, LC (damped) and/or common mode signal filters at the signal input.
With a true anti aliasing filter you may use software filters, they are more flexible.
Sometimes there are known sources of noise, like SMPS, motor controllers...then you may focus on these frequencies.
Klaus