What is the most likely diagnosis for a non-painful, raised, wart-like growth on the gingiva?

A non-painful, raised, wart-like growth on the gingiva is most consistent with a papilloma. Papillomas are benign epithelial tumors characterized by a wart-like appearance due to the proliferation of squamous epithelial cells. They typically present as soft, fleshy lesions that can vary in color from white to pink, and often have a lobulated surface. The non-painful nature of the growth, combined with its raised and wart-like characteristics, aligns well with the clinical presentation of a papilloma.

In contrast, keratosis generally presents as a thickened area of the mucosa with a rough texture, which is not consistent with the description of a raised growth. Peripheral giant cell granulomas and peripheral ossifying fibromas are both reactive lesions that often appear as firm, nodular masses on the gingiva, but they typically arise in response to local irritants and are more commonly associated with a history of dental trauma or disease. Additionally, these lesions often display pain or tenderness, especially if they are inflamed. Therefore, the characteristics of the growth described in the question point distinctly toward a papilloma as the most likely diagnosis.