What is TGA?
Truevision TGA is a fixture of game development and 3D texturing, where its straightforward layout and real alpha channel have kept it in use long after browsers stopped caring about it. Files may be raw or run-length encoded.
What is TIFF?
TIFF is the archival and print format - lossless, high bit depth, and flexible enough to hold multiple pages in one file. Scanners, publishing workflows and document archives lean on it heavily. Browsers have never displayed it, which is why it is offered here as a target rather than a source.