1.8v to 3.3v level shifter logic family
The LSF0204 will translate 1.8 to 3.3V. It requires a stiff pull-up on the high side if you care about switching speed.

The TXB0104 includes speed-up logic to improve risetime without the need for pull-up. It too can translate up from 1.8V.

Note that both these devices are bidirectional and transparent, making them flexible and easy to integrate.