1st - Field effect ( Rain Dance, Sunny Day, Hail, Sandstorm etc .. )
2nd - Reflect, Light Screen, Safeguard etc .. )
... I dont know how to elaborate but they are very often used for strategy
Why some move unavailable on some poke on playerdex, Like whirlpool on Swampert I already learned it ingame then when I change move at playerdex it gone missing ..
either;
- Your REP is not enough to battle the npc
- You already win/lost/dc to the npc
It should said on your chat box if your REP is not enough to battle, to increase REP ~ do some mini quest/pvp