Are found by going through the refrigerators/vents of various locations. Each room is blocked by Ulrika, who won't move until you find the items she requests.
Villain's Mansion: glue
Future Forest: rakes
City of Digg'ten: scrap metal
Undersea Facility: orange pylons
Digg'ten Desert: USB sticks/thumb drives
Professor's HQ: fire extinguishers
Back in Professor's Cabin: shoes, dress, scarf