Here's what we can consider:
* RomaHeta (Italy x Romania): While there isn't much official content, there are a decent amount of fan creations, especially on platforms like Tumblr and DeviantArt.
* Hetaoni (Japan x Italy): This pairing has a slightly stronger presence online, with more dedicated fan communities and artistic creations.
Ultimately, popularity can vary greatly based on specific platforms, demographics, and trends. Both ships have their dedicated fans and communities, but neither has widespread mainstream recognition.
Instead of focusing on popularity, it might be more interesting to explore what attracts fans to each pairing and what makes them unique within the Hetalia fandom.