Your bottom two sigs are the best IMO because they have nice clean edges and you don’t see any pixels. For the Blade one using some of the colors in the highlights in his face in the background would help tie him into the image much like the purple in the bottom one. With the top image the pixels that you see around the hair makes it look like a cut and paste so feathering the edges would help this.
As a side note, but this is more of a pet peeve of mine is not having text touch edges like the bottom or the side, this will draw the views eyes off the image and doesn’t help the flow. Keeping just a few pixels will help this and the flow.
We have a Signature Advice Thread for stuff like this. Use that. Thank you. And this will be getting closed soon.