The term "most seen" refers to something that is commonly observed or encountered. There are several synonyms that can be used in place of this term, depending on the context of the sentence. One such synonym is "frequently viewed", which is often used in the context of digital media, such as videos or websites. Another synonym is "popularly observed", which can be used to describe something that is widely recognized or noticed. "Commonly encountered" is another option, which is often used in the context of experiences or situations. Overall, there are many ways to express the idea of something being widely seen or observed, depending on the specific context and language used.