The Gift of Mighty Deeds or Miracles is where God's power is immensely experienced and usually defying the laws of nature. By this Gift, you perform something beyond the ordinary to give glory to God and to save others.
You can see this manifested together with other Gifts especially the Gifts of Healing and the Gift of Faith.
In the earthly life of our Lord Jesus Christ, He performed several miracles.
Everyone in the crowd sought to touch him because power came forth from him and healed them all.
-- Luke 6:19
Suddenly a violent storm came up on the sea, so that the boat was being swamped by waves; but he was asleep.
They came and woke him, saying, "Lord, save us! We are perishing!"
He said to them, "Why are you terrified, O you of little faith?" Then he got up, rebuked the winds and the sea, and there was great calm.
-- Matthew 8:24-26
Those who ate were about five thousand men, not counting women and children.
-- Matthew 14:21
-- This is when Jesus feed them with 5 loaves of bread and 2 fish in Matthew 14:13-21.
When it was evening, they brought him many who were possessed by demons, and he drove out the spirits by a word and cured all the sick,
-- Matthew 8:16
But it is also written:
And he did not work many mighty deeds there because of their lack of faith.
-- Matthew 13:58
All mighty deeds and fruits of the Gifts are all to bring everyone to God -- to build our faith and trust in Him.
More readings:
Miracles of the Saints: https://www.miraclesofthesaints.com/
St Rose of Viterbo
At the age of 3, she brought her aunt back to life.
More info: https://www.roman-catholic-saints.com/saint-rose-of-viterbo.html
Saint Louis Bertrand
He once raised a girl to life by the application of a Rosary and often attributed to the intercession of Our Lady the miraculous powers he manifested. (https://www.roman-catholic-saints.com/saint-louis-bertrand.html)
Saint Elzear of Sabran
Because of the numerous miracles that occurred at his tomb and the urgent request of the kings of France and Naples, Pope Urban V, his godchild, with great joy canonized him in the year 1369. (https://www.roman-catholic-saints.com/saint-elzear-of-sabran.html)
St. Genevieve
Paris experienced proof of Genevieve's intercession on many occasions. The most famous occurrence was the miracle of Des Ardens, or the burning fever. In 1129, a violent fever swept through the city, and doctors could not stop the people from dying. The shrine of Genevieve was carried in a procession to the cathedral, and during the ceremony, those who touched her shrine were healed by the power of the Lord. Throughout the whole town, no one else became sick, all the ill recovered and only three people died. (https://www.catholic.org/saints/saint.php?saint_id=120)
St Christina of Bolsena and St Christina the Astonishing