-A Pokémon that learns Sketch in Dragon Egg Group can be a poison spitting reptile. It might spit different colored poisons for artistic attempts.
-An alternate Onix evolution can be one that focuses on Speed and Special Defense that keeps its Rock typing, for sake of Brock.
-Slowpoke can get an Ice/Psychic evolution that is more explicitly based off a hippo, for Lorelei. This Slowpoke would probably be adapted to live in its original habitat, Seafoam Islands.
-A bunch new items and abilities can be introduced for item farming. Certain abilities can infect opponents with certain hindering items like Sticky Barb, certain moves can create and fling items to opponent such as Toxic Orb, and others can be like Pay Day and just scatter around certain items. The latter would be especially useful of Gems and Evolutionary Stones.
-Some new mechanic for Mega Stones and other forme changers can be introduced. These can be a new move that gets boost from them, it can be new species that have different formes related to them, or an ability that gets boosted by them.
-Similar to above, certain Pokémon can just farm items just being around the team or party, or in a specific location. For example, the player can store Luvdisc in a Luvdisc farm to get an amount of Heart Scales for a certain amount of steps.
-More items and moves that produce the abilities' effect can be introduced. Something like a Zorua Furcoat can cause Illusion on a Pokémon.
-Similarly, more held items can be made into abilities or moves. For example, there can be a Wisdom ability that gives the same boost as Wise Glasses.