Hint Toad

Hint Toad (formerly named Blue Toad) is one of the six members of the Toad Brigade, who acts as Princess Peach's attendants and royal guards. He is the smartest member of the brigade and often helps Mario with the use of his knowledge.

Super Mario Galaxy
In Super Mario Galaxy, Blue Toad appears as one of the five members in the Toad Brigade. Eventually, Mario comes along and saves the five Toads (including Blue Toad) in the Honeyhive Galaxy. Throughout the game, the Toad Brigade attempts to help Mario on his quest by traveling throughout the different galaxies in the search for Power Stars. In their last appearance in the game, the five Toads are revealed to have been promoted to Royal Guards due to their work of helping Mario.

Of the Toad Brigade, Blue Toad is shown to be the smartest of the five Toads and provides Mario with some very useful information about the galaxies. To show his intelligence, Blue Toad wears glasses and is known as the "smart one".

Super Mario Galaxy 2
Blue Toad is once again part of the Toad Brigade in Super Mario Galaxy 2. He, along with the other Toads in the brigade, arrives on Starship Mario after Mario clears Spin-Dig Galaxy. Once again, he is the smartest, and often gives Mario hints on how to defeat Bowser. His speech changes every time Mario clears a world.

Super Mario Odyssey
Hint Toad once again appears in Super Mario Odyssey as a supporting character, being named as such for the first time. He appears alongside Uncle amiibo to help Mario locate Power Moons scattered in every kingdom. Unlike Uncle amiibo, he charges Mario 50 yellow coins for every Power Moon location. He only appears on the Dark Side after the objective Arrival at Rabbit Ridge! is completed and does not appear at all on the Darker Side, but does appear in every other kingdom. He has the same appearance as in Captain Toad: Treasure Tracker, but now dons a safari hat.

Super Mario 3D World + Bowser's Fury
Hint Toad appears in Super Mario 3D World + Bowser's Fury as a playable character in the Captain Toad's Adventures levels when playing in multiplayer mode. He has the same appearance as in Captain Toad: Treasure Tracker. In the Bowser's Fury campaign of the game, Hint Toad is found near the peak of Mount Magmeow, trying to outrun a Conkdor attacking him, much like Captain Toad in Conkdor Canyon. Upon defeating the Conkdor, Hint Toad thanks Mario by rewarding him with a Cat Shine. Visiting Fur Step Island from then onward show him reunited with Toadette and the other Toad Brigade members Mario and Bowser Jr. find.

Captain Toad: Treasure Tracker
Blue Toad appears in Captain Toad: Treasure Tracker. He appears in some levels and will give Captain Toad a Super Gem, Super Mushrooms, or 1-Up Mushrooms when found. His appearance is similar to how he appeared in the Super Mario Galaxy titles with his signature pair of glasses. However, he now sports an explorer suit and backpack for collecting treasure much like the Captain himself.

He also helps the Captain in other missions such as following him around alongside the other members of the Toad Brigade for unlocking various secrets and helping Captain Toad obtain a Power Star. Prior to the final fight against Wingo, Blue Toad tosses a Super Mushroom to Captain Toad as he climbs to the peak of the tower to fight the bird in order to assist the Captain.

Super Smash Bros. for Wii U
In Super Smash Bros. for Wii U Hint Toad and the Toad Brigade make an appearance as a trophy. In said trophy, the members of the Toad Brigade are depicted using their Super Mario Galaxy appearance.

Super Smash Bros. Ultimate
In Super Smash Bros. Ultimate, Hint Toad makes a cameo appearance on the artwork on the Starship Mario spirit.

Trivia

 * Hint Toad shares many similar characteristics and looks similar to the characters Toadbert, Russ T. and the Toad General as they are all glasses-wearing blue-colored Toads that are intelligent.
 * In Super Mario Galaxy 2, after giving the Banktoad 1,000 Star Bits, he will wear a pair of glasses similar to Hint Toad's pair because he wants to look smart.
 * In Super Mario Galaxy 2, in the Boulder Bowl Galaxy, Hint Toad will be picking at the ground with a pickaxe. He says he lost his glasses, but upon closer examination using the first-person view, he is actually hitting his glasses with his pick.
 * In Super Mario Odyssey, the guide that Hint Toad holds has a map of Bob-omb Battlefield from Super Mario 64.