The comic book Challengers of the Unknown # 52 (October - November 1966) had a very brief yeti cameo.
In the issue, the villains Villo and Brainex are watching the past exploits of their nemeses, the Challengers of the Unknown, on a video screen, looking for weaknesses. They see the Challenger named Red Ryan throwing a yeti off a mountain. Brainex notes, "[Red] is a pretty canny combatant! He was a famed mountain climber - and experienced in every hazard! He could cope with any danger and emergency!" (Source)
That emergency being yeti.
In a (no-doubt) direct nod to Red's yeti-hurling moment in # 52, a yeti can be spotted in the opening sequence of episode 3 of Season 2 of Batman: The Brave and the Bold cartoon (2010).