Ratty Tatty by Kevin Richey of FontForge is a free distressed cartoon display font with blunt, uneven strokes and a deliberately battered silhouette. The letters look hand-cut and cheerfully unruly.
Children's event posters are a particularly good match because the lopsided forms have a mischievous, handmade bounce. The same rough humor suits toy packaging, comic covers, and scrappy band merchandise. Against doodled monsters, torn-paper shapes, or collage textures, the lettering can become part of the illustration instead of behaving like a polished caption.