Anything that can boost your size category will boost the damage of your claws. Wands/Scrolls of Enlarge person, Psionic Tattoos/Dorjes of Expansion. Likewise, since you'll be making multiple attacks on the same round, anything that can boost your damage per attack will be helping you, so other Psychic Warrior powers like Metaphysical Claws, that other Psywar power that gives Energy Damage to claws as well. AFAIK there are a few items that grant rage as well - since that boosts your strenght it can help with both to-hit and damage so it's something to consider - as well as flat strenght bonuses from Tomes/Other items.
Really, boosting claw damage is more or less the same as boosting weapon damage, when you take out the weapon enhancement bit off of it. There's energy damage, size increases, strenght increases, touch attacks & miscellaneous damage boosts, such as those from charging & other maneuvers/feats/class features.