Basically, you make your own medicine item or berry.
Hero's Potion: Restores HP fully and ups all stats slightly, but must protect the other pokemon on the team from attacks for one turn, only usable in double or triple battle.
Alert Orb
Raises all stats by one stage when under 25% health.
Heat Powder: Fully heals a fire type pokemon's HP, PP, resets stats and statuses. If used on another type of pokemon, it burns them.
Lightning Powder: Fully heals an electric type pokemon's HP, PP, resets stats and statuses. If used on another type of pokemon, it paralyzes them.
Cryogenic Powder: Fully heals an ice type pokemon's HP, PP, resets stats and statuses. If used on another type of pokemon, it freezes them.
Neuro Powder: Fully heals a poison type pokemon's HP, PP, resets stats and statuses. If used on another type of pokemon, it badly poisons them.
Spore Powder: Fully heals a grass type pokemon's HP, PP, resets stats and statuses. If used on another type of pokemon, it puts them to sleep.
Shining Powder: Fully heals a normal type pokemon's HP, PP, resets stats and statuses. If used on another type of pokemon, it confuses them.
Quigon Berries look like a yellow pomegranate, and reduce the damage taken by super effective Light Type moves.
Lokin Berry: Has a 60% chance of fully healing you and upping all your stats one level, but a 40% chance of killing you.
Now I made some berries that disable attacks of a certain type from working at all. One for each type.
Restoring Potion
Revives all of your team but only works when only one Pokemon is remaining on team.
Pumkin Berry
A sour berry shaped like a pumpkin. It defrosts a Pokemon when eaten.
(not the same as the E-reader berry under the same name and effect, fun fact I made this up before knowing that was a thing!)
Shadow Berry
Transforms the eater into a Shadow Pokemon.
Incin Berry
Restores a Pokemon's HP a lot in a pinch, but it's so spicy it burns the Pokemon.
Cocoa Berry
A tasty cocoa pod berry! It restores a Pokemon's full HP but is so sweet it lowers its Attack and Defense while also raising its Speed.
Crystal Berry
When eaten by a Pokemon, it increases its Defense and Special Defense drastically but lowers Speed and freezes it solid. It tastes somewhat sour and somewhat sweet.
Ghast Berry
A very spicy pepper berry that adds the Ghost type to the Pokemon that eats it.