From Halopedia, the Halo wiki
Powerups are gameplay items that enhances player traits for a duration. They are commonly featured in multiplayer maps in Halo: Combat Evolved, Halo 2, Halo 3, Halo 4, Halo 2: Anniversary, and Halo 5: Guardians and can be added via Forge in Halo 3, Halo: Reach, Halo 4, Halo 2: Anniversary, and Halo 5: Guardians. They are also featured in the campaign of Halo: Combat Evolved and Halo 2.
List of powerups
The following is a list of power-ups throughout the Halo first-person shooter titles.
List of buffs
The following is a list of buffs that are similar to power-ups but are only applied when carrying mythic weapons in Halo 5: Guardians. As long as the weapon is equipped and has ammo/charge, the buffs will be applied.