In how many forms the energy in this Cosmos exists?

In the context of physical sciences, several forms of energy have been defined. These include:

Thermal energy, thermal energy in transit is called heat

Chemical energy

Electrical energy

Radiant energy, the energy of electromagnetic radiation

Nuclear energy

Magnetic energy

Elastic energy

Sound Energy

Mechanical energy

These energies may be divided into two main groups; kinetic energy and potential energy. Other familiar types of energy are a varying mix of both potential and kinetic energy. Energy may be transformed between these forms.

The above list of the known possible forms of energy is not necessarily compete. Whenever physical scientists discover that a certain phenomenon appears to violate the law of energy conservation, new forms may be added, as is the case with dark energy, a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe.

Actually before Einstein,scientists used to think mass and energy are two different things.But Einstein proved that energy can be converted into mass and vice versa.So there is only 1 form of energy,and its convertible from one form to another.

Energy is an expression of Power. According to Indian Philosophy power is Absolute and is the possession of Providence. When manifest into a 'State of Duality' as subject-object relationships that absolute power is converted into a potential power known as 'Maya' beheld by Providence. Initiating 'Action' (sans.=Kriya) from the potential power of Maya three forms of 'Energy' (sanskrit=Shakti) are created and Providence becomes the Absolute Source or Cosmos (Hiranya Garbha) as all mighty Universal Lord of all Manifest Creation. The three 'Forms' of Energy permeating Cosmos are: 1) Iccha Shakti or Power of Desire, 2)Gjnana Shakti or Power of Knowledge and 3) Kriya Shakti or Power of Dynamic Action. Shakti is synonymously used in sanskrit as both potential energy or 'power' or as 'energy' of action releasing through power. Note that both power of desire and knowledge as 2/3 majority belong to the Subtle Mind and only 1/3 belongs to the relativistic physical world by virtue of which Einstein has arrived at the famous formula after deep pondering.