The most usual material that cross-leg tables are made out of is wood. Sometimes the wood will be distressed, as in a farmhouse aesthetic; in other cases, the wood will be painted—or left natural, as in a modern rustic minimalist vibe.
Other materials tend to include glass with wooden legs, and wood with metallic legs. Ultimately, the main feature of a cross-leg table is its cross legs; feel free to enjoy any material that would work well for you!