Below is a list of bonuses the various Metroid-related amiibo unlocks in Metroid Dread:
Dread Power Suit Samus: unlocks one additional Energy Tank. This is a permanent upgrade.
E.M.M.I.: unlocks one additional Missile+ Tank. This is a permanent upgrade.
Zero Suit Samus, Samus (Smash Bros. Series), and Samus Returns Samus: completely refills your energy, once per day each.
Ridley, Metroid on Glass Tube, and Dark Samus: completely refills your ammunition, once per day each.
Walkthrough | Maps & Routes | Missile Expansions | Missile+ Tanks | Power Bomb Expansions | Energy Tanks | Energy Parts | Boss Fights | E.M.M.I. Encounters | Shinespark Puzzles | Special Abilities | Chozo Archives | Endings | Sequence Breaks | amiibo