"Powerful buffs" refers to enhancements or bonuses that greatly increase the strength or abilities of someone or something. It suggests a significant upgrade or boost in power. Full definition
Rebuild the realm to recruit troops previously only available during events, receive powerful buffs at different traders, and access the new Expeditions. (nonfictiongaming.com)
Individual weapons can be broken down and re-forged with powerful buffs, but you must access an entirely separate area of the game to equip those weapons. (eurogamer.net)
The Chanter does as his name sort of implies, continuously chanting a serious of songs and stores that serve to awake surrounding spirits, unleashing a steady stream of powerful buffs and even the ability to summon up skeletons. (wolfsgamingblog.com)