In the game's English manual, the "Fokkeru" enemies in the Great Palace seem to have been misinterpreted as some sort of bizarre alien entity by the artist. If you get a closer look at their in-game sprites, you'll see that they're actually bird-headed harpies... with fully exposed breasts.
If you buy a Secret Medicine from Crazy Tracy, she'll apply it by rubbing it on Link while calling him "big guy" and giggling. Though there's no sort of visual you get to exactly show what's happening, the flirtatious text is still there.
The amount of sense this makes varies between versions. The Secret Medicine's inventory sprite in the original GB/GBC versions is a bottle of red liquid, but in the Switch remake, it's a jar full of cream, which adds some extra context as to why applying it requires it to be rubbed on the body.
One 'blink and you'll miss it', The Fairy Queen, who is very wise despite looking like a little girl and repeatedly calls Link child, showing there's a significant ill-defined age gap, says he's her type. Link being anywhere between 9 and 12 makes it worse.
Groose being turned on over the thought that Zelda made the sailcloth, and the fact that the sailcloth's description says in tiny text (just after Zelda has taken it of herself) "...It smells nice too...". Word of God confirmed that they tried as best they could to hide in many adult moments while still keeping it an all-ages game.
Ghirahim sure talks a lot about the exquisite beauty of his own form... while the camera shows off his figure at different angles... and he makes sensual little grunts...
TriForce Heroes has the Stylish Woman, who comments amorously on Link's attire whenever he tries on a new costume. Her flirts remain innocent enough, for the most part, but then there's the line when he comes out wearing Linebeck's Uniform (which, for reference, allows you to glimpse the contents of unopened treasure chests)
Stylish Woman: Oh, my little jumbo shrimp!♥ What are you staring at? My treasure is your treasure! Hehe!
The Stylish Woman's dialogue during the Playable Epilogue, during which she mentions wanting to add "a little oomph to [her] va va voom." She goes on to point out Link's supposed blushing and claims he's "so easy to fluster."
A literal example: In certain places throughout the world, you can find Koroks, who will give you "Korok seeds" as a reward for finding them. They look like small golden turds, the flavor text mentions their "distinct smell", and Hestu, the lead Korok, is hesitant to discuss what they actually are. Should the player collect all 900, Hestu will give you their own “seed”, which is far bigger, is said to smell terrible, and is directly modeled after the Golden Poo.
To upgrade Link's armor, the Great Fairies (who, for the record, are positively titanic in this game) incorporate various means of flirting with him, culminating in them snatching him up and hugging him close as they retreat beneath the water of their fountains. If that doesn't speak for itself, one of them admits when you first meet her that she was expecting someone bigger, but that a "slim little lad" like Link will do just fine.
Stay at the Gerudo inn and choose the spa plan. Romah's dialogue and especially the giggling at the end seem to suggest that Link may have gotten more than just a massage.
In thanks for providing flint and saving Isha’s jewelry shop, Cara the assistant jeweler will offer to tell Link various secrets about Isha. One of them is that Isha sleeps in nothing but her “accessories”, to which Cara wonders if she gets cold at night.
If the player completes the entire Hyrule Compendium, Symin will reward them with the Classified Photo, which is said to be “a photograph of a beautiful young woman of the Sheikah tribe”. The photo cannot actually be seen, but it’s heavily implied to be a picture of Purah.