The language of the universe is what it is coded in, and knowing it allows you to edit that code. The code is geometrical in nature. Even if you do not use it to change reality, it will empower your spells tenfold.
The circle stands for cycles, eternity and infinity.
The triangle stands for ascension, godhood, spirits, and the planes above ours.
The square stands for earth, creation, life, and the physical realm.
The meaning of the rhombus is As Above, So Below.
The sphere represents gravity and the law of attraction.
The pyramid is the stairway to godhood, the path to ascension.
The icosahedron represents the universe itself and all things within.
The Merkaba is the symbol of energy.
The pentagram stands for, as some believe, the five elements.
Here on out are symbols that were not, at first, believed to be magickal, but they were revealed to me as such by the grey mist. All the names are made up by me.
The Askana is a focal point. Use it to focus energy passed through it into a single point, no matter how much you pass through.
The Juharti serves the opposite purpose of the Askana, dispersing energy that it is directed at, even if that energy is solidified into matter.
The Marana is a portal that can bring you any spirit, and any amount of any energy, as well as bring you to anywhere in the three higher planes, or bring something else there.
The Alkani is the symbol of omnipotence, through it, any amount of energy can be focused to any goal, which will be completed as fast as possible with the given energy.
The Sanhani is the symbol of Omniscience, scrying into it will grant you specific knowledge about what you need to know, or what you request of it.
The Guharati is the symbol of omnipresence, it can bring you anywhere you wish (but not physically) even if you wish to be everywhere. It can even bring you outside our universe.
Those are the symbols of the universe that I know of right now.