The airtubs make minor appearances in Mario & Luigi: Paper Jam, attacking Peach's Castle alongside Neo Bowser Castle and airlifting Toadette's Papercrafts. (mariowiki.com)
Hammer Bros. make minor appearances in Mario & Luigi: Superstar Saga, which (for the most part) takes place in the Beanbean Kingdom. (mariowiki.com)
A couple of humans make a very minor appearance in the story, but the POV character is a mystical version of a redwood sapling. (independentbookworm.com)