I know what you mean, I think I have over half dozen bands for mine.
I have these and they are nice:

https://www.amazon.com/Compatible-Frontier-Stainless-Replacement-Smartwatch/dp/B07P8SP3SX/ref=sr_1_34?keywords=samsung+s3+watch+bands+magnet&qid=1553968466&s=gateway&sr=8-34

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a little problem I have is because it is magnet and if i'm not careful it will stick to stuff, I have a Macbook Pro and if i'm not careful it will stick to it..