Optional Content

Side activities in the Switch 2 version that the story never asks you to do.

A cow for Link's House

You need Epona for this, so it is an adult-era task.
At Lon Lon Ranch, take on the obstacle course. Jump the fences and reach the goal in under 40 seconds. Clipping an obstacle costs you extra time.
When you succeed, a cow is delivered to Link's House in Kokiri Forest. Play Epona's Song next to it with an empty bottle to fill up on Lon Lon Milk.

All other cows

Every cow gives Lon Lon Milk if you carry an empty bottle and play Epona's Song. One bottle holds two servings, and each restores four hearts.

Hyrule Field: in a grotto near the road to Gerudo Valley. Blow up the rock that hides it.
Lon Lon Ranch: in the stables at the north end.
Kakariko Village: in the stable in the south of the village. Reach it by dropping from the neighbouring roof – use the Hookshot on the vines beside the house, or let Kaepora Gaebora carry you down from the Death Mountain summit.
Death Mountain Trail: in a grotto halfway up the mountain, hidden under a rock you can blow up.
Gerudo Valley: as a child, glide with a Cucco to the riverbank near the waterfall on the west side.

The Running Man

Selling the Bunny Hood: as a child, borrow the hood from the Happy Mask Shop (50 Rupees). The Running Man jogs laps around Lon Lon Ranch in Hyrule Field. Catch up with him while wearing the hood and he pays with a Gold Rupee worth 200.
The race: as an adult, talk to him in the tent in Gerudo Valley to race to the bridge in Kokiri Forest. No route is fast enough to beat him, so treat it as a time trial and try to lower your own record.

Mini-games

Fishing Pond (Lake Hylia, 10 Rupees): a big enough catch earns a Piece of Heart as a child (10 pounds) and the Golden Scale as an adult.
Shooting Gallery (10 Rupees): break all 10 targets. The one in the Market gives a Bigger Deku-Seed Bag, the one in Kakariko a Bigger Quiver.
Bombchu Bowling (Market, child, 10 Rupees): opens once you own the Bomb Bag. Three stages reward you with a Bigger Bomb Bag, a Piece of Heart and Rupees.
Dampé's Grave-Diggin' Tour (Graveyard, child, 10 Rupees): he walks the graveyard between 18:00 and 21:00. One of the dig results is a Piece of Heart.
Dampé's Race (Graveyard, adult): keep up with his ghost for the Hookshot. Finish in under a minute on a later run for a Piece of Heart.
Skull Kid Sessions (Lost Woods, child): repeat three melodies on the stump for a Piece of Heart.
Frog concert (Zora's River, child): the Song of Storms earns one Piece of Heart. After playing them all six non-warp songs, win their game for another.
Treasure-Chest Game (Market, child, night, 10 Rupees): in each room one of two chests holds the key. The Lenses of Truth show which, and the last room holds a Piece of Heart.
Super Cucco game (Lon Lon Ranch, child, 10 Rupees): find three Cuccos in 30 seconds to win a bottle of Lon Lon Milk.
Diving game (Zora's Domain, child): the free first round, with five scales to collect, awards the Silver Scale. Later rounds cost 10 Rupees and pay 20.
Horseback Archery (Gerudo's Fortress, adult, Epona and Gerudo Token): score 1,000 points for a Piece of Heart and 1,400 for the Biggest Quiver.

Mask trades

Give Zelda's Letter to the guard at the north gate of Kakariko Village to open the Happy Mask Shop in the Market. Each mask has to be sold on, then paid for, before the next one is offered.

Keaton Mask (10 Rupees): sell it to the Kakariko gate guard for 15.
Skull Mask (20 Rupees): sell it to the Skull Kid in the Lost Woods for 10.
Spooky Mask (30 Rupees): sell it to the boy in the Graveyard for 50.
Bunny Hood (50 Rupees): sell it to the Running Man for 200.
Complete all four to receive the Mask of Truth. Wearing it on the Forest Stage in the Lost Woods earns the Biggest Deku-Nut Bag, and the Skull Mask the Biggest Deku-Stick Bag.
The trades cost more than you carry at first, so collect 10 Gold Skulltulas for the Adult's Wallet beforehand.

Richard the dog

At night, look for a small white dog in the back alleys west of the Market plaza. Several dogs roam there; Richard is the white one that spins when you interact with him.
Lead him to his owner south of the fountain for a Piece of Heart. Repeating this later pays a Blue Rupee.

The Scarecrow Song

As a child, visit Bonooru, the scarecrow with the green scarf at Lake Hylia, and play him any eight-note melody that is not one note repeated. Remember it – it becomes your Scarecrow Song.
When Navi turns green at certain spots as an adult, play it to summon the scarecrow Pierre and Hookshot over to him. Several Gold Skulltulas are only reachable this way.

Great Fairy Fountains

Play Zelda's Lullaby in a fountain and pay the offering. Start at Death Mountain Trail or Hyrule Castle, as the other Great Fairies will not appear until you have met one of those two.

Death Mountain Trail (25 Rupees): Din's Fire and the Magic Meter. Bomb the wall next to the owl at the summit.
Hyrule Castle (50 Rupees): Spin Attack. Bomb the boulder in the rocky alcove past the gate.
Zora's Fountain (100 Rupees): Farore's Wind. Bomb the boulder in the southeast corner.
Death Mountain Crater (200 Rupees): Magic Meter upgrade. Smash the rock pile on the west side with the Megaton Hammer.
Desert Colossus (300 Rupees): Nayru's Love. Bomb the cracked wall between the three palm trees on the north side.
Outside Ganon's Castle (500 Rupees): Defense upgrade. Lift the pillar on the east path with the Golden Gauntlets.

Before the final battle

Make a manual save before the last boss. Loading after the ending puts you back at your last save, so that save is your way back to the open world.
The game keeps only five autosaves and overwrites the oldest, so keep a manual save you can rely on.