Ipapa Berry - You'll spot the Ipapa Berry tree just after starting on the route.
TM73: Thunder Wave - Just north of the tree is a boulder. Push it out of the way with Strength then head forward to find a rock puzzle. Use Strength again to push the boulder here down twice, right three times, up twice, right three times, up once, and right five times to drop it into the hole. Now you can grab the item on the other side.
Mind Plate - Lying in the southeast corner of the rock pillar section.
X Accuracy - Lying on the western edge of the first rock fence.
Thunder Stone - Lying against the second rock fence.
Soft Sand - In the southwestern corner of town.
Timer Ball - It's hard to see, but this is in the northwest corner of the field behind the Hotel Marine Snow.
TM66: Payback - Speak to the man the in the suit inside the Pokémon Center to receive this.
Speed Power Lv. 1 (O-Power) - Head to far right room on the second floor of the Hotel Marine Snow. Mr. Bonding is here again, and he's got another item for you.
Everstone - Speak to the scientist inside the cabin behind the Pokémon Center to receive this.
Sitrus Berry - You'll spot the Sitrus Berry tree soon after entering the route.
Super Potion - Examine the crystal up the first set of stairs to obtain this.
TM69: Rock Polish - Up the next set of stairs is a tree. Slip between the crystal and the stairs and use Cut to clear the way. Slide down the slope to the north to reach this.
Hyper Potion - Head south from the Cave of Reflection entrance to spot this on a grassy ledge.
Cave of Reflection
Nest Ball - Follow the branching path north to find this near a mirror.
Revive - Take the east branch of the path to find this in a dead end.
Moon Stone - Now follow the path south to spot this atop a set of steps.
Black Belt - You'll spot this to the east soon after descending the cave's lower floor. Just ascend the steps to reach it.
Escape Rope - This one can't be missed; you'll spot it when you enter the southern part of the cave's lower floor.
Hyper Potion - Lying against a mirror in the northern half of the cave's lower floor.
Iron - In the northwest corner of the same area.
Earth Plate - Descend into the cave's lowest level, and you'll see this along the path. Note that this area is full of swooping Pokémon.
TM74: Gyro Ball - In the same area, run alongside the mirror to spot a door you can't otherwise see. Head inside to find this move.