Julio Urias, Jose De Leon and Yadier Alvares can be found in packs. Check them out below. There are three main kind of cards available (Clear Auto Gray, Metal Auto Silver and PURE Auto Charcoal), along with numerous parallels, but only Urias is available in each one. De Leon can be found as a Metal Auto Silver and PURE Auto Charcoal card. Alvarez can be found only as a Metal Auto Silver card. Frankly, I don't exactly know what are the main differences between the three different kind of cards, so I show a general example of what they look like below.
Of note, there is a fantastic 1990 Leaf Kirk Gibson autograph buyback card available, as well. They are numbered to 40 copies.
Jose De Leon Julio Urias