Like with Pokémon's previous iterations, this game has various people dotted around the region who have the ability to aid you in various ways. This page is to detail those characters

IV Judge
Location: Route 11/12 Gate

The IV Judge is once again a function within the game and not by going to a certain person, but it requires unlocking. To unlock it, you need to find Professor Oak's aide in the gate between Routes 11 & 12. If you have 30 Species of Pokémon registered in your Pokédex then he will unlock the feature. This feature is found in each Pokémon's summary screen by pressing Y or shaking the controller.

Statements

Specific IVs
IV Total Statement
31Best
30Fantastic
26 to 29Very Good
16 to 25Pretty Good
1 to 15Decent
0No Good
IV Total
IV Total Statement
151 to 186Amazing Stats!
121 to 150Great Stats
91 to 120Good Stats
0 to 90Ok Stats

Madam Celadon - Nature Manipulation
Location: Celadon City

As breeding is not a feature within these games and Pokémon don't have abilities, there is no easy ways to manipulate wild Pokémon natures, except by one character. In Celadon City's Pokémon Center, you will find Madam Celadon. For 10,000, she will ask you a question asking you which colour of flower you choose to water. This determines the dominant stat. Then, she'll ask which one you'll thin out indicating the hindered stat. She'll then tell you which nature you'll see more prominently in the wild for the rest of the day.

Colour Associated Stat
RedAttack
YellowDefense
BlueSpecial Attack
GreenSpecial Defense
PinkSpeed
Hyper Training
Location: Route 5

Introduced in Pokémon Sun & Moon, Pokémon Let's Go, Pikachu! & Let's Go, Eevee! include Mr. Hyper. When you have defeated the Elite Four, if you have a Pokémon that has hit Level 100 and have a Bottle Cap item, Mr. Hyper will artificially boost the IV of a Pokémon's stat up to max

Move Reminder

Location: Indigo Plateau

The Move Reminder is once again one of the most important Move Tutors in the game. Located in the Indigo Plateau, this character will teach your Pokémon a move that it has in its Level Up learnset, including moves that it wouldn't learn until a later level. This is done in exchange for a Heart Scale which can be found by playing with Pikachu.

Happiness Checker

Location: Pallet Town

In Pallet Town, you can talk to your rival's sister and she will tell you how happy your Pokémon are with you. This is done with a specific phrase. This is especially more important in this game as Pokémon with max happiness have a 10% boost in stats.

Statement Values
{Pokémon} really, really, really loves you! I can tell you really trust each other! 250+
I can tell {Pokémon} really likes you. It’s saying it wants to always be with you! 200-249
It seems like {Pokémon} likes being with you! 150-199
You’re really starting to get friendly! I’m sure you’ll be best friends in no time. 100-149
Seems like it’s starting to like you! I’m excited to see how you two grow. 50-89
Oh, I guess you just met, huh? Well, I’m looking forward to seeing you become fast friends! 1-49
Maybe it gets KO’d a lot in battles...? 0
Poké Ball Replenishment

Location: Mt. Moon, Rock Tunnel, Seafoam Islands, Victory Road

In the various caves of the Kanto Region, you will often find a man in a corner of the cave. If you ever have 9 or less Poké Balls, the man will give you 10 Poké Balls so that you can get back to catching. This comes at no cost..