Use these cards to support your X-Saber monsters. Saber Slash works well with X-Saber Wayne because he helps you swarm the field allowing you to destroy more cards with Saber Slash. At One With the Sword gives your X-Saber monster a significant boost and allows you to draw when it destroys an opponent's monster but you can only activate it when you control only 1 monster. Sparkling Sword allows you to destroy another card your opponent controls whenever the equipped monster destroyed a monster by battle. Saber Vault gives your X-Saber monsters some boost to their stats depending on their level.
It's funny, this is actually best outside of X Sabers because it's generic, easy to summon, and if you special a level 2 or 3 tuner warrior monster from the hand (not sure if we have any level 2s yet but we do have a level 3) that's a level 7 or 8 synchro monster right there.