In Crash Team Racing Nitro-Fueled (2019 Remake / Remaster) you can unlock Penta Penguin on PS4, Xbox One, and Nintendo Switch. Penta is a secret character with maximum speed stat.

To unlock Penta Penguin, go to the main menu and enter the following button combination:

PS4: Hold L1+R1, press Down, Right, Triangle, Down, Left, Triangle, Up
Xbox One: Hold LB+RB, press Down, Right, Y, Down, Left, Y, Up
Nintendo Switch: Hold L+R, press Down, Right, X, Down, Left, X, Up

When done correctly you will hear a sound and see an icon in the bottom left corner. You can then pick this character before any race.