Super Mario 64: Castle Secret Stars, Cap unlocks for the Red Blue and Green Boxes

As well as the stars in every level in Super Mario 64, there's a handful of stars hidden elsewhere.

Castle Secret Stars - Super Mario 64 DS Guide - IGN

Super Mario 64: Castle Secret Stars, Cap unlocks for the Red Blue

Super Mario 64 (Game) - Giant Bomb

The Princess' Secret Slide - The Castle's Secret Stars - Super

3D All-Stars Guide: All Castle Secret Stars in Super Mario

Super Mario 64: Jolly Roger Bay Stars - Plunder in the Sunken Ship

Super Mario 64 Switch, Fantendo - Game Ideas & More

Whomp's Fortress - Super Mario Wiki, the Mario encyclopedia

Every Hidden Star location in Super Mario Galaxy - Polygon