The physical appearance of Ruto as an adult and all of the Great Fairies. The fairies are women wearing nothing more than vines and leaves to cover themselves. Some of their positions might be questionable as well. The game developers later were able to change Ruto's design and hide her breasts. The Great Fairies replaced their vines with skimpy leopard skin bikinis.
There's also Nabooru's 'present' to Link:
Nabooru: I want to ask you a favor... Will you go into this tiny hole and get a treasure that's inside?
You can Hookshot onto the nipples of the statue in the Spirit Temple (the one at the entrance of the boss room). Only the nipples and only while directly looking at them.
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 getting 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.
TriForce Heroes has the StylishWoman, 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.
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.