Hi, and welcome to the forum!
You can customize types and tags in version 6. For Tags you can either right-click the tag in the Tags window and choose Properties, or type the tag name in instant search, activate the tag and modify the color there. Just as in 5.x, you can only change the color, not add a Thought Icon. New to 6.x is the ability to add files and attachments. For Thought Types it's changed a little from 5.x. They are now viewable in the Plex, so you no longer need the old Thought Type window. You can either use Options > Thought Types Window and click on the Type to activate it in the plex, type the name in instant search to pull it up, or in the Thought tab (yes, the name and layout changed a bit) there is an arrow in a circle next to the Type name. Click it to activate the type. From there you can modify the Type as you would a regular thought, either add a color, or Thought Type icon. If it helps, you can find the PersonalBrain 6 Beta Transition guide here.
Java SE 6