.tpl

files are containers for images. They are used in New Super Mario Bros Wii, Mario Kart Wii, and many other games. They are even used in the Wii menu.

TPL stands for Texture Palette Library.

TPL files can be contained within a Wii U8 Archive  file, or directly accessible through the filesystem. In NSMBW,  files can be found in several   files, for example in. The  file here is called.

files are usually inside the folder  , if they are stored inside archives.

In Newer Super Mario Bros Wii, .tpl files can additionally be found in the folder.

File Format
A  file consists of one or more images:

The file header starts always at offset. All other part are linked by offsets. All offsets are relative to the beginning of the file header.

File Header
The file header consists of 12 bytes:

Image Offset Table
The image table contains one pair of values for each image:

Palette Header
The palette header usually occurs directly after the file header, at the address specified in the image offset table.

The palette data address is relative to the start of the file. The palette format values are listed below.

Image Header
The image header normally occurs after the palette header and data. The image data usually follows, after padding to the nearest  bytes.

The image data address is relative to the start of the file.  Source: File Header Information by Tockdom (modified) 

Image
The image data itself is encoded using the same implementations of each of the formats as TEX0 files. It can be exported to a  file.

Tools
The following tools can handle  files:
 * BrawlBox/BrawlCrate (multi-purpose)
 * CTools ("Image Tool")
 * Wiimms SZS Tools (multi-purpose; can modify BREFT, BTI, TEX0, TPL and  images
 * Wexos's Toolbox