I have a way to do that, not sure if its the best.

Whenever you open the component in appbuilder, the `window.location.href` contains `flexipageEditor/surface.app?` . You can use that to your advantage.


    <aura:component implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,forceCommunity:availableForAllPageTypes,force:lightningQuickAction" access="global" >
    	    
        
        <aura:handler name="init" value="{!this}" action="{!c.doInit}"/>
        <aura:attribute name="isAppBuilder" type="String" default="false"></aura:attribute>
        
        
        <aura:if isTrue="{!v.isAppBuilder}">
        	My Component in App Builder
        </aura:if>
    
    </aura:component>

JS: 


    ({
        
        doInit : function(component, event, helper){
            if(window.location.href.includes('flexipageEditor/surface.app?') ){
                console.log('In App Builder');
                component.set("v.isAppBuilder" , true);
            }else{
                 console.log('Not App Builder');   
            } 
        }
    })

So here your isTrue block will only show if your app is viewed in app builder.

The only drawback is when SF changes their URL format for app builder, then this logic wont work.