In itself, the evidence was not enough to prove him guilty. [Considering only the evidence, and nothing else was not enough...]
Of itself [same thing - people often say "in and of itself" - again, same thing]
I built the box by myself [I did it alone, and without help.]
I built the box on my own [same as above]. I'm living on my own [I am supporting my self financially].
The robot is walking by itself [It is walking without help].
I have come here on my own accord [I decided to come here without anyone telling me to do so].