There are many ways I can interpret from that question.
MILD SPOILER ALERTS - READ AT YOUR OWN RISK
The guardians get a boost in their power in the 3rd Saga या so, when they learn the ability to become invisible. And Cornelia learns to heal.
The guardians get a new power in the 7th Saga in the comics, where the strength of their powers multiply, and they are equipped with a new outfit. ---- In season 2, Will learns to use Quintessence, and सूखी घास, घास Lin can become Invisible, Will can talk to furnitures, Irma can manipulate the mind, Cornelia learns telekinesis, and Taranee can use telepathy.
Sorry if my answer is not what आप expected, it's been a long while since I've read/watched W.i.t.c.h, and I don't remember a lot of things.