“i believe” (CCLI # 4956918) is a song based on the creed, as such is overtly states a belief in the Trinity. It would work well during the preparation of gifts. “Your love” (CCLI # 4957388) and “alleluia to the Lord” (CCLI # 4956774) would both work for a Communion / Communion reflection song. “Your love” speaks to the unity of the trinity based on love. Alleluia to the Lord is a great song of praise to the Trinity.