Okay looks really good for a beginner!
Ill give you some points you might work on!
Point 1.
Try to use some less colors. If you use all colors into one signature it might be chaotic.
Point 2.
Try to use borders! It looks a little bit more modern and cooler.
Point 3.
As I see, your renders are good! Altho i saw on signature 2 that the icebear has a right line on the left of it. Try to avoid that!
As said, it looks good for a beginner! If you need more help just PM me or reply on this topic

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