When searching for synonyms for the phrase "niggardly of appreciation," there are a variety of options to choose from. One common alternative is "stingy with gratitude," which notes a similar reluctance to express appreciation or offer thanks. "Unappreciative," "ungrateful," and "thankless" are all additional options that highlight a similar lack of acknowledgement or gratitude. For a more nuanced tone, synonyms like "parsimonious" or "uncharitable" might also be applicable, noting a tight-fistedness or unwillingness to give praise or credit where it's due. However you choose to phrase it, acknowledging the importance of appreciation and gratitude can help build stronger relationships and more positive environments.