Finding materials that are both low density, strong, and good conductors of heat is a bit of a challenge, as these properties often conflict. Here's a breakdown:

Low Density: This generally means the material has a lot of empty space within its structure.

Strong: This refers to the material's ability to withstand stress without breaking or deforming.

Good Conductor of Heat: This means the material readily transfers heat energy.

Here are some materials that partially meet these criteria, but no single material excels in all three:

* Aluminum: Lightweight, strong, and a good conductor of heat, making it a popular choice for many applications. However, its strength may not be as high as other materials.

* Magnesium: Lightweight, relatively strong, and a decent conductor of heat. Its strength-to-weight ratio is excellent, but it's not as strong as aluminum.

* Carbon Fiber Reinforced Polymer (CFRP): Extremely strong and lightweight, but it is a poor conductor of heat. It can be used in combination with other materials to improve thermal conductivity.

* Graphene: A very strong and lightweight material with excellent thermal conductivity. It's still in its early stages of development and mass production is a challenge.

Important Considerations:

* Trade-offs: It's difficult to find a material that excels in all three properties. You will often need to prioritize one property over another.

* Specific Application: The ideal material will depend on the specific application.

* Emerging Materials: Researchers are constantly developing new materials with improved properties, so the possibilities are evolving.

Let me know if you have a particular application in mind, and I can offer more specific recommendations.