I'm assuming by 'buffed', you mean a raise in one of the Pokemon's base defense stats.
Defense
- Pikachu (30 ⇒ 40)
- Ampharos (75 ⇒ 85)
- Bellossom (85 ⇒ 95)
- Roserade (55 ⇒ 65)
Special Defense
- Pikachu (40 ⇒ 50)
- Alakazam (85 ⇒ 95)
- Victreebel (60 ⇒ 70)
- Jumpluff (85 ⇒ 95)
- Exploud (63 ⇒ 73)
- Staraptor (50 ⇒ 60)
- Gigalith (70 ⇒ 80)
- Leavanny (70 ⇒ 80)
All base stat changes (including Attack, Sp. Attack and Speed) all added +10 to the stat.
All base stat changes can be found here: http://www.serebii.net/xy/updatedstats.shtml
Hope I helped. :)