1 #Blocks Blocks
These classes can be used to modify blocks in the WordPress editor. You can add these classes to the Additional Class section in the advanced panel on the block editor.
Most commonly I imagine they will be added to paragraph blocks but the styles will work on any block.
          Source: 
    assets/sass/style.scss, line 32
        1.1 #Blocks.border Border Blocks
Add a bit of oompf to your blocks to make them stand out a bit more.
            Examples
          
            
              Default styling
            
          
              .block-border
            
            
              The common shadow border.
            
            
              .block-border-dashed
            
            
              A less common dashed border.
            
            Markup
<div class="[modifier class]"></div>
          
          Source: 
    assets/sass/lib/theme/_alt-blocks.scss, line 116
        1.2 #Blocks.intro Intro Block
A larger font size to give a bit more emphasis to an article introduction.
            Example
          
          This is the intro to a block and it stands out really nicely I think.
            
          Markup
<div class="block-intro">This is the intro to a block and it stands out really nicely I think.</div>
          
          Source: 
    assets/sass/lib/theme/_alt-blocks.scss, line 102
        1.3 #Blocks.status Info Block
A block for sharing status information.
            Examples
          
            
              Default styling
            
          Info relevant to the block goes in here!
            
          
              .block-info
            
            
              This is an information block.
            
            Info relevant to the block goes in here!
              
            
              .block-help
            
            
              This is a help block.
            
            Info relevant to the block goes in here!
              
            
              .block-alert
            
            
              This is an alert block.
            
            Info relevant to the block goes in here!
              
            
              .block-success
            
            
              This is a success block. Well done!
            
            Info relevant to the block goes in here!
              
            
              .block-error
            
            
              This is an error block.
            
            Info relevant to the block goes in here!
              
            
              .block-announcement
            
            
              This is an announcement block.
            
            Info relevant to the block goes in here!
              
            Markup
<div class="[modifier class]">Info relevant to the block goes in here!</div>
          
          Source: 
    assets/sass/lib/theme/_alt-blocks.scss, line 2