I can think of one or two, and that's excluding the nuclear attacks on Hiroshima and Nagasaki.
WW1 Mines: On 7th June 1917 the British set off 19 mines hidden in tunnels under German trenches at Messines killing 10,000 German troops.
This Explosion Was the Biggest Blast Before Atomic Bombs.
Shipwrecks.
SS Eastland:One of the worst maritime disasters in U.S. history occurred on July 24, 1915, when the SS Eastland capsized on the Chicago River. Packed with Western Electric employees on their way to a company picnic, the Eastland sank within yards of shore. Of the estimated 2,500 people on board at the time, more than 800 were killed.
SS Sultana: On April 27, 1865, the deadliest maritime disaster in U.S. history occurred when the side-wheel steamship SS Sultana exploded on the Mississippi River just north of Memphis, Tennessee. The American Civil War had ended just weeks before, and repatriated Union prisoners of war, having endured hellish conditions in Confederate military prisons, were eager to return to their homes in the North. To facilitate that journey, the federal government paid steamship operators handsomely for each soldier they carried. That practice led to astonishing levels of corruption as well as neglect of the most-basic safety concerns. In the case of the Sultana, that meant cutting corners on the repair of a leaky boiler and carrying as many as 2,300 people—more than six times the vessel’s rated capacity. When the overtaxed boiler ruptured, hundreds were killed in the initial explosion, and more were trapped when the overloaded decks collapsed. Although some 1,800 people were killed, the incident was largely overshadowed in the press by the ongoing coverage of the Lincoln assassination.
SS Kiangya:In late 1948 communist forces had gained the initiative in the Chinese Civil War, and thousands fled the Nationalist stronghold of Shanghai before the advancing People’s Liberation Army. On December 4, 1948, the SS
Kiangya was officially carrying 2,150 refugees—almost double its rated capacity—but several thousand more had crowded onto the steamer before it left the docks. The ship exploded at the mouth of the Huangpu River, most likely as the result of its striking a World War II-era mine. Perhaps 1,000 passengers were rescued, but as many as 4,000 were killed in the explosion and subsequent sinking.
RMS Lusitania: Perhaps the highest-profile casualty of Germany’s policy of unrestricted submarine warfare during World War I, the RMS Lusitania was attacked by a German U-boat on May 7, 1915, and sank in just 18 minutes. The ship was regarded as a legitimate target by the Germans, as they believed that it was being used to transport war matériel (evidence has since emerged that the Lusitania was, in fact, carrying more than 170 tons of artillery shells and ammunition at the time of its sinking). Nevertheless, the loss of 1,198 passengers, including 128 Americans, would eventually serve as casus belli for U.S. involvement in World War I.
MV Doña Paz: Maritime traffic has played a vital role in the growth and development of Southeast Asia, and ferries transport hundreds of millions of people throughout the region each year. Accidents have been far too common an occurrence, however; in the 21st century alone, international regulatory agencies documented some 17,000 fatalities as a result of ferry sinkings in Southeast Asian waters. The worst such accident—indeed, the deadliest civilian maritime disaster in history—occurred on December 20, 1987, when the passenger ferry MV Doña Paz collided with the oil tanker MT Vector in the Tablas Strait, roughly 110 miles (180 km) south of Manila. Eager to reach their destinations prior to the Christmas holiday, an estimated 4,300 people (more than double the ship’s official capacity) had crowded onto the Doña Paz prior to its departure from Tacloban, Philippines. At the time of the collision, no senior officers were on the bridge of the Doña Paz, the Vector was traveling without a lookout, and it is likely that both ships lacked a functioning radio. Despite clear visibility and relatively calm seas, neither ship gave any indication that it was aware of the other. The collision ignited the 8,800 barrels of oil and gasoline on the Vector, and both ships were quickly engulfed in the blaze. Of the more than 4,400 passengers and crew on both ships, just 26 people were rescued from the oil-slicked waters.
MV Wilhelm Gustloff: The MV Wilhelm Gustloff was the pride of the Nazi Kraft durch Freude (“Strength Through Joy”) program, which provided leisure activities for German workers and served as an important propaganda tool for the Third Reich. The ocean liner carried holidaymakers on cruises of the North Atlantic and the Mediterranean, and, with the outbreak of World War II in 1939, it was converted into a hospital ship. It later served as a floating barracks and, in the closing months of the war, was called upon to evacuate German troops and civilians from East Prussia ahead of advancing Soviet armies. By that time, in accordance with the laws of war, the Wilhelm Gustloff had shed the white paint and red crosses that had marked it as a noncombatant, and the presence of troops on board and antiaircraft guns on deck made the ship a viable military target. Refugees streamed into the port of Gotenhafen (now Gdynia, Poland) in the hopes of escape, and thousands crowded onto the Gustloff. Built to accommodate 1,900 people, the ship left port on January 30, 1945, carrying an estimated 10,000. Just after 9:00 PM that evening, three torpedoes fired by a Soviet submarine slammed into the port side of the Gustloff. Ice had rendered many of the ship’s lifeboats inoperable, and the crew members best trained to deal with an evacuation had been killed in the torpedo attack or were trapped below deck. The Gustloff slipped below the frigid Baltic waves just over an hour later. Although rescue efforts began within minutes of the ship’s initial SOS call, only 1,200 people could be saved. The sinking claimed 9,000 lives, making it history’s deadliest shipwreck.
So some examples and I also didn't include the RMS Titanic.
