Cynthia is an orange juice carton that Scott brought home after Mildred went missing. He began showing her around, only to run into Mildred when she unexpectedly returned, prompting him to hide Cynthia awkwardly behind his back.
Dennis (Stuffed Bear)
Dennis is a stuffed bear belonging to Balthazar Cavendish. When Cavendish was moping after having lost his job, Dakota asked if he'd like to bring Dennis on vacation. After finding out they'd gotten new jobs, Cavendish hugs Dennis in delight.
Horseface the Equestrian Barbarian
Horseface the Equestrian Barbarian is a roadside attraction seen in Family Vacation.
The Singing Saw
The Singing Saw is a marketing item that appears in "Battle of the Bands". It appears after Zack returns from getting snacks and finding out The Lumbermaxes will be competing in the Battle of the Bands with Milo using it. A cutaway advertisement then shows that it plays the song Saw Away at my Heart when used to saw something, although the ad mentions that it is for entertainment purposes and is not actually meant to cut wood.
According to Max, it is hinted that there are other sets of tools that sing, but only a saw is featured in the episode.
Lardee-Oh's are a cereal brand sponsored by Lard World and its mascot, Lardee Boy. It seems to be comprised of large scoops of chocolate ice cream.
It is featured on a billboard in The Llama Incident, which ended up playing a part in said incident when it fell on Balthazar Cavendish and Vinnie Dakota.