In shulchan aruch yorei deia 141 it says that it is assur to make a picture of a dragon.
Would it be assur to make a dragon out of Lego?
They have Lego Chima with dragon types if creatures, would this be assur ?
The Shulchan Aruch (Yoreh De’ah 141:3) rules that it is permitted to create the form of a dragon (see also Gra 19), and that the only concern is to keep it at home on account of chashad (suspicion). Today, there is no issue of suspicion concerning dragons, and therefore no prohibition will apply.