Procedural vs Seamless Textures

For instance the Procedural texture can be used with metal objects while Seamless Texture can be used with wooden objects, node maps examples are below:

Metal Procedural Textures

Wooden Seamless Textures

Fabric Seamless Textures

Leaf Transparent Textures

To add a transparent texture

1. Add plane
2. Add a transparent alpha channel leaf PNG for the plane shading
3. Set Material settings > Settings > Blend Mode to ‘Alpha Clip’ & Shadow Mode to ‘Alpha Clip’
4. Make sure to change the plane dimensions to match the original PNG dimensions then you can scale in Blender