There are currently 24 man-made, or synthetic, elements. Examples include curium, einsteinium and bohrium. Additionally there are a further 9 elements, that while present on earth in trace amounts, are usually synthesized.
While the synthetic elements do not naturally occur on Earth, it is thought that they may have been present at one time, but have since disappeared due to their instability and short half-lives. The synthetic elements are: Americium, Curium, Berkelium, Californium, Einsteinium, Fermium, Mendelevium, Nobelium, Lawrencium, Rutherfordium, Dubnium, Seaborgium, Bohrium, Hassium, Meitnerium, Darmstadtium, Roentgenium, Copernicium, Nihonium, Flerovium, Moscovium, Livermorium, Tennessine, Oganesson..
Those elements that are found in trace amounts on Earth, but typically produced through synthesis are: Technetium, Promethium, Polonium, Astatine, Francium, Actinium, Protactinium, Neptunium, Plutonium.
Many of the man-made elements are named after scientists or historical figures. Curium, first identified in 1944, was named after Marie and Pierre Curie. Rutherfordium was named after Ernest Rutherford, the father of nuclear physics. Researchers identified rutherfordium by bombarding plutonium with neon ions. Einsteinium gets its name from theoretical physicist Albert Einstein. Researchers from Berkeley identified einsteinium in the debris created by a thermonuclear explosion.