Besides gold and fine linen, which colors of yarn were used for Aaron's holy garments?

Answer: Blue, purple and scarlet

The holy garments for Aaron and his sons were made with gold, blue, purple and scarlet yarn, and fine linen.

“These are the garments that they shall make: a breastpiece, an ephod, a robe, a woven tunic, a turban, and a sash. They are to make these holy garments for your brother Aaron and his sons, so that they may serve Me as priests. They shall use gold, along with blue, purple, and scarlet yarn, and fine linen.”— Exodus 28:4-5 (BSB)