Taken from IMBD: Marjorie Temple, owner of a bus line and an apparently worthless plot of land, is set upon by rich oil speculators who know her land actually is worth millions. When they try to put her out of business for good, young race driver Burn 'em Up Barnes comes to her rescue - again and again and again. This is a 12 part serial. Links to all chapters are available below.

Ray 'Crash' Corrigan, a recent graduate of Annapolis, travels with Professor Norton, his Son Billy, and plucky reporter Diana Compton to the Undersea Kingdom of Atlantis to locate the cause of series of earthquakes. When they arrive Crash and his friends become embroiled in battle between warring Atlanteans.

From IMDB:When the ancient continent of Mu sank beneath the ocean, some of its inhabitant survived in caverns beneath the sea. Cowboy singer Gene Autry stumbles upon the civilization, now buried beneath his own Radio Ranch. The Muranians have developed technology and weaponry such as television and ray guns. Their rich supply of radium draws unscrupulous speculators from the surface.

Taken from IMDB: A 12-episode serial in which a son avenges the death of his father at the hands of corrupt politicians. He develops a wide variety of complex devices in his crusade . . .

Taken from IMDB: A scientist discovers a formula for making synthetic gold, but before he can reveal the secret to his colleagues at the International Research Foundation, both he and the book in which he has written the formula disappear. Super-detective Craig Kennedy and his partner are called in to find both the scientists and the formula.

Taken from IMDB: A 12-episode serial in which a son avenges the death of his father at the hands of corrupt politicians. He develops a wide variety of complex devices in his crusade . . .

Taken from wikipedia: The Green Hornet Strikes Again! (1941) is a Universal movie serial based on the The Green Hornet radio series by George W. Trendle. It's a sequel to the earlier, 1940 serial The Green Hornet. This was Universal's 117th serial (the 49th with sound) of the 137 the studio produced. The plot involves racketeering and is unusual for a film serial in having mostly stand alone episodes instead of a continuous story (although this was also the case for the original Green Hornet serial).

Taken from IMDB: A 12-episode serial in which a son avenges the death of his father at the hands of corrupt politicians. He develops a wide variety of complex devices in his crusade . . .

Lloyd Bridges stars as secret agent X-9, in this series that is based on a comic strip. Released in 1945, the action takes place in 1943, during WWII. There's no real secret to this agent, everyone on Shadow Island calls him "X-9," and knows he is an agent for the United States. Shadow Island is neutral, and the Japanese agents are also known. There is one person that is truly undercover, and another that is kept a secret, until the final chapter. X-9 wants whatever the Japanese are after; but doesn't know it's a formula for turning distilled water into aviation fuel.

Phantom of the Air (1933) - Tom Tyler - 12 Chapter Movie Serial from Universal Pictures Inventor John Edmunds (William Desmond) is working on a device called the Contragrav, a machine that defies gravity and can enable a plane to fly without a pilot. He and his daughter Mary (Gloria Dea) enlist the help of airborne Border Patrol captain Bob Raymond (Tom Tyler) as a test pilot to help them complete Edmunds' work on the Contragrav. However, airborne importer (and secret smuggler) Mort Crome (LeRoy Mason) has got wind of the Contragrav, and will stop at nothing to get it.