Mark on user profile

Hello again! I was wondering if there's a way (or a plugin) to make different users (other than admins, guests, etc), with a mark on the profile.
Something like, maybe: a senior member, a frequent poster... each with some kind of stamp or mark on the user profile and profile pic.

Yes, it's how I have a helmet icon next to my name. You don't need a plugin to do this as it's just built in.

Our substitution API supports IF conditions. You can use those IF conditions to add extra content to field layout parameters (like for the formatname field) to display additional information or in a Custom HTML field. See the bottom of our substitution tutorial below.

www.joomlapolis.com/documentation/127-community-builder/279-tutorials/18353-using-substitutions-throughout-cb

You can check if they have a specific field value, check if they have a specific view access level, or even if they've a specific Joomla usergroup.

Sorry to ask, but I can't get through. I made a new field (cb_userstatus), checkbox type, with 3 options in the value rows. Where am I supposed to insert the html code?
Btw, I first added the field in a new Tab, but I guess I could avoid this using an existing tab (like profile foto). Is it so?
 

Sorry to ask, but I can't get through. I made a new field (cb_userstatus), checkbox type, with 3 options in the value rows. Where am I supposed to insert the html code?

Depends on what you want it to display and where. If you just want it to display something different on profile then you can use the profile layout parameters. Under Parameters > Layout use the Profile Value Layout to customize how it displays on profiles. Example as follows.

You're basically conditioning against the fields value with these IF substitutions. It will then display whatever you put inside the IF substitution. In my example it's just text, but this could be an image if you wanted.

Btw, I first added the field in a new Tab, but I guess I could avoid this using an existing tab (like profile foto). Is it so?

You can add it to an existing tab, yes.