When LotR TCG began, there was only one format: the cards that existed. With the release of The Two Towers, Decipher split the game into three formats:

• Fellowship Block, allowing cards from The Fellowship of the Ring, Mines of Moria, and Realms of the Elf-lords
• Towers Block, allowing cards from The Two Towers, Battle of Helm's Deep, and Ents of Fangorn
• Open, allowing cards from all sets, except for Fellowship Block sites

There is no X-list or Restricted list for Towers Block. Decklists for Towers Block can be found at this subforum of the Last Homely House.