(If you are new to MCU, then you should start with; Iron Man, The Incredible Hulk, Iron Man 2, Thor, Captain America and then Agent Carter.)
Stark Expo 1974 - commercial for Stark Expo 1974 in Flushing Meadows in New York.There are four different Stark Expo 2010 videos:
They take place during Iron Man 2 and you can easily find them by googling for them.
Peggy Carter’s 1953 Smithsonian Interview - Where Carter is being interviewed about Steve Rogers (can be found at youtube)
S.H.I.E.L.D spin-off mini-series Slingshot can be found at ABC's youtube channel.
Peter's To-Do List (Short Film - Spider-Man: Far From Home - Blu-Ray) - short extra clip when Peter is picking up his passport.
Marvel Cinematic Universe (#1-4) tie-in comics :