List of sponsors in Mario Kart DS
From the Super Mario Wiki
This a list of the sponsors that have only appeared in Mario Kart DS. For the sponsors that have appeared in at least one other title, see the List of recurring sponsors in the Mario Kart series.
Fresh is a sponsor that appears in Mario Kart DS. Presumably, it is some sort of transportation company for fresh fish, specifically Cheep Cheeps. The logo consists of an image of a Cheep Cheep based on those from Super Mario Bros. 3 on a blue wave with a yellow gradient background. The text is written in an all capitals light blue font with a shadow effect. It is advertised by means of Cargo trucks.
Luigi GP is a sponsor that appears in Mario Kart DS. The sponsor's purpose is not entirely clear but its name suggests it relates to Luigi. The "GP" could stand for Grand Prix. The logo consists of the company name in a black font with a red shadow effect on a yellow background. The word "Luigi" is underlined in black, and a black checkered section appears at the end of the underlining and fades around the "GP". Three billboards displaying the logo appear before the finish line.