All the precious metals and stones came from Egypt. That we know.
It is also possible that certain animals and plants that were necessary to build the mishkan were found in the desert. The gemara even says that the rare Tachash animal - with its one horn coming out of its forehead - only existed at that one moment in history. Moshe found one, they made the Mishkan curtains from it, and then it became extinct.
If the Gemara is to be taken literally and Moshe was able to find a unicorn in the desert then it is not such a stretch to believe that in the desert they also somehow found some Hilazon snails whose blood was needed for the Techelet dye.
Rashi is bothered by the question of where the materials came from and he quotes a midrash regarding the trees that they used.
"Where did they get them? Rabbi Tanchuma explained that our forefather Jacob foresaw through Divine inspiration that Israel would one day build a Mishkan in the desert so he brought shittim trees to Egypt and planted them and commanded his sons to take them with them when they would depart from Egypt."I always loved this Rashi. Imagine, over 250 years earlier, when Yaakov already knew that the Jews would be stuck in Egypt for an indefinite period he planted these trees and with those trees he also planted hope For two centuries when the Jews were in the depths of despair from brutal slavery they could visit the trees of Yaakov and remember his promise that one day Hashem would take them out and they would be free to build a Mishkan and serve Hashem as a free nation!
But the trees planted by Yaakov had to be maintained. Every generation drew inspiration from the trees as children, but when they reached adulthood it became their responsibility to care for the trees so that future generations would be able to draw inspiration from them as well.
This week we welcome a new baby boy into the Jewish community. Mazal Tov to Rabbi Mizrahi and to Talia and to Yael and their extended families. His bris in shul this shabbat will be a great simcha for our community and may he grow up inspired by the Mizrahi's household of Torah and may he one day grow to build a Torah household for himself.