Higher Voltage Inputs
A 74HC4049 or 74HC4050 can be powered at 2V to 6V and will accept input voltages up to +16V (pin out is same, 74HC4049 just inverts the logic state).
4049 is basically the same but consumes a bit more current and has a min supply voltage of 3.5V.
Higher Voltage Outputs
A SN7417 is a 5V powered logic buffer which has open drain outputs that can drive loads up to 15V @ 30mA. SN7407 will do up to 30V @ 40mA and is cheaper
Logic To Darlington (open drain driving of higher voltages, relay switching etc)
Logic To Source Driver Array (+V driving of higher voltages, relay switching etc)
MIC2981. 8 outputs. Logic input (3/5V). 5V-50V 500mA rated outputs (de-rate for multiple outputs used at the same time). Be aware that the transistor drive outputs will drop 1.7V up to around 2.2V depending on the load.