The home page of the crwflags host does have a copyright notice attached. I have not located the 1st flag (Castile and Leon) in public domain yet. The 2nd flag (white flag sown with fleurs de lis) is PD . The 3rd flag (Flag of Mexico) is PD. The 4th flag (Flag of Texas) is PD. The 5th flag (U.S.) is PD. The 6th flag (1st CSA) is PD. You can also find some PD images for different Buffalo Soldier Calvary Regiment Coat of Arms by drilling down.
Many flags for cities in Texas are found PD.