Before offering you gift ideas for confirmation, it is good to say a word about the age of confirmation and the nature of this sacrament.
In France, confirmation is conferred between 12 and 18 years after the first communion; confirmation is considered a ratification of baptism. This practice, which is important in the choice of a gift, is erroneous nevertheless as recalled Bishop Minnerath of Dijon, in pastoral orientations in 2014: The The sacrament of confirmation, the second stage of Christian initiation . We invite you to read this very interesting letter. Confirmation is not a ratification of baptism, but an anointing that strengthens or completes baptism. This anointing and the laying on of hands symbolize the gift of the Holy Spirit received by the apostles on the day of Pentecost. This sacrament should be conferred before the first communion.
the Holy Spirit, received on the day of confirmation, is the third person of the Holy Trinity. Therefore a gift idea for a confirmation would be a religious icon that represents the mystery of Pentecost where the Holy Spirit descended on the apostles gathered in the Cenacle. An icon of the Holy Trinity is also an ideal gift for a confirmation. All these gifts are suitable for either a girl or a boy.
If by confirmation, the grace of baptism is strengthened, the new confirmed one becomes like an adult Christian able to give the reason of his faith and to testify to it publicly. Another gift idea could highlight this aspect of this Christian mystery. A crucifix is very suitable because in the memory of the Passion of Christ, the martyrs found the strength to witness to their faith to the blood. A rosary is a classic gift for such an event: by prayer and especially by rosary prayer the Christian will find the necessary strength for daily fidelity in his Christian commitments. Of course any rosary is enough, but a precious rosary is a simple mean that can help to carry on this Marian prayer.
The gift will obviously depend on the age of the confirmand: for a boy or a girl who receives the confirmation before the first communion, that is to say at the turn of the age of 8 - 10 years a religious icon or a statue religious seems more appropriate; on the other hand, if he is much older, he may be offered a book of a tried and tested spiritual doctrine such as the Imitation of Jesus Christ, the Way to the Perfection of St. Teresa of Avila, or a book by St. Alphonsus.