Sheikhul Islam, may Allah have mercy upon him said, the best awliyaa are those that have the greatest knowledge of what was given to muhammed 3alayhi sallatu wassalaam, and the geatest followers.
Theres a book written by Al-Imam Al-laalakaa'ee called "karaamatul awliyaa" it mentions some wonderful stories, but be wary of some of the asaaneed.
Also in kitaabul fataawa by Sheikh ul Islam may Allah have mercy upon him theres a chapter on this.
I like the story of usair bin hudhair, may Allah be pleased with him. (found in Bukhaari and kitaab al-laalaaka'ee)