I am aware that the antidoron given to the faithful after the liturgy is from the bread which was blessed by the priest but not used in the Holy Communion. In terms of Scriptural parallels, is the antidoron considered to refer to the loaves and fishes, to manna in the desert, both of them or another case? I don't doubt its spiritual significance, I was just curious as to whether people like to relate it to certain verses more than others. Thank you.

The Slavs underline it by using 5 loaves for the Proskomedia. The practice of antiodon comes from discontinuing the practice of given the Faithful Eucharist to take home for during the week. So the Eucharist connections-manna, multiplication of loaves, etc-is always present.