OldSansBlackUnderline

Old Sans Black Underline, by M. Klein, is a free underlined sans display font with a blunt, early-digital boldness. The letters are heavy, plain, and compactly confident, while the continuous underline becomes the real signature, turning the alphabet into something halfway between a headline tool and a built-in sign strip.

It fits poster titles, album covers, zine mastheads, protest graphics, and storefront-style branding where that solid rule can lock words together fast. As a free font, it also makes sense for short title cards, bold web banners, and monograms, because the underline gives even simple caps a ready-made base line and a slightly stubborn attitude.