I’ve been diving deep into anime and romance novels for years, and while polyamorous themes are still niche, there are a few adaptations worth mentioning. 'Koi to Uso' (Love and Lies) explores a dystopian love triangle with polyamorous undertones, though it’s more about societal pressure than true polyamory. 'Domestic Girlfriend' has messy, complicated relationships that flirt with the idea, but it’s more drama-heavy than a genuine poly representation.
For something closer, 'Yuri!!! on Ice' isn’t explicitly poly, but the emotional bonds between characters go beyond traditional romance, giving a vibe that fans of polyamory might appreciate. The anime scene is still catching up to this theme, but manga like 'Kimi no Koto ga Dai Dai Dai Dai Daisuki na 100-nin no Kanojo' (The 100 Girlfriends Who Really, Really, Really, Really, Really Love You) is a chaotic, over-the-top take on polyamory. It’s not for everyone, but it’s a start.