... give an example of something with a beginning that has no cause.
Since you have provided no example of something with a beginning that had a cause why should anyone bother. Other than a few quantum events that may or may not have had a beginning everything that happens is the result of a chemical or physical recombination of existing things.
A few billion years ago a galaxy of main sequence stars seeded itself with dust clouds composed of oxygen, nitrogen, carbon, hydrogen, iron and other low molecular weight elements via the well-defined carbon sequence of fusion events. A few were in a configuration to produce novae where higher molecular weight elements could form. These dust clouds in the galaxy www.youtube.com/watch?v=m06aoq3qw7k formed more stars and inertial and gravity effects formed planets around them. Some of those planets were at the right distance from their star to have liquid water in abundance (hydrogen and oxygen are common in the universe) and carbon does its promiscuous chemistry to generate organic compounds that clump together to make things like lipid membranes and large clumps of goo. Some of those large clumps of goo replicate inside a lipid bubble, and make more bits of replicating goo. Some replicators are more successful at gathering resources than others and dominate the ecosystem they are in and life goes on.
Perhaps you can find a beginning in all of that and we can discuss whether or not it had a cause.