This (due to the force for magnetic energy) cause things to float.

Electro mag suspension

A magnet made of an insulated wire coiled around an iron core (or any magnetic material such as iron, steel, nickel, cobalt) with electric current flowing through it to produce magnetism. The electric current magnetizes the core material.

Electromagnets. When an electric current flows in a wire it creates a magnetic field around the wire. By winding the wire into a coil we can strengthen the magnetic field. Electromagnets are made from coils like this.

Works by constantly altering the strength of a magnetic field produced by electromagnets using a feedback loop. In most cases the levitation effect is mostly due to permanent magnets as they don't have any power dissipation, with electromagnets only used to stabilize the effect.

It is generally free, to the public, but it costs around like 10-400 depending on the amount and the durability

Extremely common

High speed travel with cars, trains, and hover type boards

When a current passes through a wire, a magnetic field around that wire is generated. The strength of the generated magnetic field is proportional to the current through the wire. When a wire is coiled, this generated magnetic field is concentrated through the center of the coil. The strength of this field can be greatly increased by placing a ferromagnetic material in the center of the coil. This field is easily manipulated by passing a varying current in the wire. Therefore, a combination of permanent magnets with electromagnets is an optimal arrangement for levitation purposes.[4] To reduce average power requirements, often the electromagnetic suspension is used only to stabilise the levitation, and the static lift against gravity is provided by a secondary permanent magnet system, often pulled towards a relatively inexpensive soft ferromagnetic material such as iron or steel. Works by constantly altering the strength of a magnetic field produced by electromagnets using a feedback loop. In most cases the levitation effect is mostly due to permanent magnets as they don't have any power dissipation, with electromagnets only used to stabilize the effect.

Permanent magnet, dense metals

This tech is generally hidden under the road or looks like a sleek train track. Doesn't have a specific look to it

Varies

Varies

Usually black, gray