There is no magic shade of blue. Color selection is subjective and completely arbitrary. Choose a shade you like, ask people around you if they like it, adjust as needed, and that's it.

But! The most important thing when choosing colors, is choice of secondary or more colors. A poor pairing of colors is immediately noticeable by almost all users and can be very off putting. I like use a color wheel tool like this one:
[paletton.com...]

Another important point when selecting colors is font color in relation to background colors, you need to make sure that the font is readable. This seems obvious, but for items like buttons and links and other page element this can be an issue, and don't forget to check for hover, and active states as well.

As NickMNS said, it's subjective.

Also remember that everyone has a different display and the colour will look slightly different.

If you really want to invest time, either carry out user testing of button colours, or run a/b testing on a live site. Do remember, it's all subjective.

[edited by: engine at 5:45 pm (utc) on Dec 16, 2021]

#CDF

:: insert ROFL emoticon ad lib ::

I think he is looking for the web color equivalent to the brown noise.
[youtube.com...]

So any designer here who could recommend me some attractive blue colors (hexcode)? Thanks!

My favourite blue is Royal Blue [en.wikipedia.org...] however, I really cannot say if it would suit your own design of the site. It may look awful, or it may match beautifully. Only you can tell, or your designer.

I'd suggest you look at a colour wheel, of which there are many examples online, and plenty of free generators. Example [color.adobe.com...]

Here's 23 to choose from:

[rapidtables.com...]

All are subjective. What specifically do you mean as "graphic elements"?

Aside: I never see "colors" on the web since I run high contrast accessibility modes (black background, white text, links yellow, visited green) as enforced choices).

That said, I do deal with colors for images, etc. and one thing to keep in mind when designing sites is look at the EMOTIONAL impact of colors. See:

[londonimageinstitute.com...]

Thanks guys these tips are exactly what I was looking for :-)