There are many synonyms for the term "heart-expanding" which are both poetic and meaningful. Some of the synonyms include touching, moving, emotional, inspiring, affecting, uplifting, warming, elevating, and enriching. Each of these synonyms has a unique tone and can be used to describe different experiences and moments. For example, "touching" might describe a heartfelt moment shared between loved ones, while "uplifting" might describe the feeling of hopefulness and positivity that comes from seeing others succeed. Ultimately, all of these synonyms embody the idea of something that makes the heart feel full and alive, and can help us express the deep emotional experiences that shape our lives.