I don't like the most of them mostly, because I don't like the style you have used in your signatures, but I have to admit that I like number 3 since it goes smooth with the render and background I also like the colors & text that were used.
That black triangle on the first signature at the right you should remove that don't know if you like that because I don't. The rest is fine such as the render fits with the color.
Second signature it looks a bit pixely however those colored shapes
The last signature there are some things wrong such as colors fractal doesn't fit with the rest. The background looks like a blury resized stock and the text looks strange.
Note that you don't have to agree with me since I'm just telling my opnion about it.
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Still it's a good job ^^,