You (and a lot of members here) seem to think that a signature is a: 'complex'/c4d background coupled with a character render at the edge or somewhere, and a text slapped onto them.
A (great) signature is one that stands out with a new formula or idea, this is were one's creativity kicks in.
But to be honest, they are better than my first attempts at signatures; back in 2008, I made my first one, and it was more less the same formula as above, albeit a bit worse. I remember using PS to put the render in front of the background, then I used MS Paint and Arial font for my username.
For superior signature ideas, please have inspiration from mine :D.