Quantum physics is a fascinating place, sometimes likened to a zoo, full strange noises and unexpected surprises!
If you take a tour of the subatomic zoo, you will see that there are many, many subatomic particles, not all of which are considered 'fundamental' or 'elementary' within the current theory of particle physics (known as the Standard Model).
In order to make sense of what would otherwise seem like total nonsense, physicists have engaged the services of mathematicians to seek out patterns and maintain some logic to what would otherwise appear as nothing short of mind-bogglingly paradoxical.
According to the (current) 'Standard Model' of particle physics, there are 12 fundamental particles: six of them are called 'quarks' and six of them called 'leptons'. Collectively, these are all called 'fermions' because they follow a statistical law called the 'Fermi-Dirac' distribution, in which, at any given time, no more than two such 'fermions' can exist with a certain amount of energy at a particular point in space.
In addition to the 12 fundamental fermions, there are 5 fundamental 'gauge bosons' which are the 'force carrier' particles, responsible for the four fundamental physical forces of gravity, electromagnetic, strong and weak force. Bosons 'mediate' the interaction (forces) between the particles. They therefore act as like the 'glue' which bind the other particles together.
For example, quarks can not exist on their own, but are 'bound' into composite particles (known as 'hadrons') by the strong nuclear force. This force, conveniently enough, only acts over very short distances! Composite particles made up of 3 quarks are called 'baryons'. These include the humble proton and neutron which are no longer considered 'elementary' particles. Other hadrons include 'mesons' which are made up of a quark and it's anti-quark.
There are of course many other such composite particles (hadrons) predicted by the Standard Model which have not been discovered yet, hence the significance of the Large Hadron Collider in helping scientists discover the existence of these subatomic particles and confirm (or refine) the theories. The existence of some of these 'new' hadrons may not be a complete surprise to some, as they are predicted within the Standard Model.
The major 'discovery' of the Large Hadron Collider was confirmation of the Higgs boson, which was the last elementary particle (according to the Standard Model) to be observed.
Whilst discoveries such as these, which confirm the existing theory are important, physicists are also looking for experimental data which may help confirm one theory over another, particularly in areas which are not explained within the existing model.