Does Red Brambleback work with Battlefield Conquer effects?

Yes, Red Brambleback works with battlefield conquer effects.

According to its text, "Your conquer effects for conquering here trigger an additional time." When you conquer the battlefield where Red Brambleback is present, your conquer effects (both those on your units and those triggered by the act of conquering) will trigger once for the conquer action itself, and then trigger an additional time due to the Red Brambleback ability.

Important Considerations:

• Conquer Requirement: As per RiftJudge FAQ #6745 and Rule 465, you must successfully perform a Conquer game action for these effects to trigger. If you cannot score the battlefield (for example, if you already held it this turn), you cannot conquer it, and therefore no conquer effects—including those enhanced by Red Brambleback—will trigger.
• Trigger Sequence: When you conquer the battlefield, the standard conquer event occurs, and the additional trigger from Red Brambleback is added to the chain as a pending item, effectively doubling the output of your conquer effects.

Note: This interpretation is based on the card text of Red Brambleback and standard rules for conquer triggers. As noted in the retrieved FAQs, this assumes you have not already scored the battlefield this turn, as you can only score a battlefield once per turn (Rule 465).