Event weapons are your best bet, til then craft Ultimate Mumei swords. A cheap alternative and not the greatest but cheap to upgrade wih decent atk.
Since you didn't list who or what you have for ToK to inherit, im going to assume you dont have any SSRs or URs ready to be inherited. In that case, aim for the SRs with atk/dmg and also with speed. Speed is important for ToK to activate her only skill worth using her for.