Move power/accuracy changes
Around 20 or so moves got its base power changed from Gen IV to Gen V. However, this move alone faced a decrease in base power, from 50 BP to 30 BP.
What is Feint?
This move that has a chance to raise the user's defense by 1 stage in Gen VI can raise the user's defense by 2 stages instead in Gen VII
What is Diamond Storm?
This move's English name gets a change in its name from Gen VII to Gen VIII
What is Vise Grip? (From Vice Grip)
Within Generation V (in Pokemon Black and White Version 2) this pokemon got its ability reckless changed out
What is Basculin?
This is the most common addition to abilities in Gen VIII, with 4 abilities now also doing this.
What is Blocks Intimidate?
Prior to its base power change from Gen V to Gen VI, this move's base power used to be a weird 14 BP
What is Pin Missile?
This move 33.2% chance to lower the target's Special in Gen I became a 10% chance to lower the target's Special Defense in Gen II. (If I'm not wrong Special is like only in Gen I where it later split into Special Attack and Special Defense)
What is Psychic?
What is Conversion2? (From Adaptation2)
This pokemon with only 1 ability in Gen III got a second one, Mold Breaker, in Gen IV
What is Pinsir?
This ability that did not use to cause to user to take damage now causes the user to take damage in Gen VIII
What is Disguise?
This move's accuracy greatly increased from 65% in Gen I to 90% in Gen II
What is Rock Throw?
This move's 40% chance to poison in Gen I fell to 30% in Gen II
What is Sludge?
This move's Spanish name is changed from Gen I to Gen II, and gets another change from Gen IV to Gen V
What is Quick Attack? (Ata. Rápido to At. Rápido, then At. Rápido to Ataque Rápido)
This pokemon's hidden ability was Quick Feet in Gen V but became Speed Boost in Gen VI
What is Venipede/Whirlipede/Scolipede?
This ability now reduces the amount of Wild Pokémon encounters when lead in the party in Gen VIII
What is Infiltrator?
This move's base power increased by a whopping 4 times from Gen VI to Gen VII.
What is Leech Life?
This move gets a 20% chance to confuse in Gen II, despite having no additional effect in Gen I
What is Dizzy Punch?
Of the 4 moves to get a name change from Gen II to Gen III, this is the only one that is a status move
What is Focus Energy?
This pokemon obtained the hidden ability Anticipation in Gen VI though it didn't have it in Gen V
What is Ferrothorn?
This ability could no longer affect evasion or accuracy stats in Gen VIII
What is Moody?
This move's accuracy went from 55% in Gen III, to 80% in Gen IV, to 100% in Gen V. That's a massive improvement.
What is Disable?
This damaging move originally had a 33.2% chance to lower the opponent's defense by 1 stage in Gen I. In Gen II, this chance dropped to 10%. In Gen III, it now has a 10% chance to lower Special Defense instead.
What is Acid?
This move's German name is changed from Gen I to Gen II, then changed back in Gen III
What is Transform? (Wandler to Verwandler back to Wandler)
A bunch of pokemon received a second ability in Gen IV. These 2 were tied for the most common ability to be newly obtained.
What is Rivalry and Technician?
This ability now increases chance of encountering Grass-type Pokemon when lead in the party as of Gen VIII
What is Harvest?