At 1MHz you can use just about any kind of oscillator you like: crystal, LC or RC will all work and are practical, each has its advantages and disadvantages.
Does it need to be adjustable?
A crystal oscillator is very stable but it's not very adjustable unless you use a PLL which is complicated.
RC and LC oscillators aren't quite as stable but at least the frequency can be easily adjusted.
I don't see how a PLL would increase how much a crystal oscillator can be adjusted.
With a fundamental crystal, you can adjust by maybe +/- 500ppm at most. An overtone crystal can't be adjusted nearly as much. A PLL can only automate the adjustment, it can't increase it.
The BH14xx FM stereo transmitter ICs use a single 7.6MHz crystal oscillator and a frequency sythesizer using a PLL to obtain 4 different FM channels that are selected with a DIP-switch.
I don't see how a PLL would increase how much a crystal oscillator can be adjusted.
With a fundamental crystal, you can adjust by maybe +/- 500ppm at most. An overtone crystal can't be adjusted nearly as much. A PLL can only automate the adjustment, it can't increase it.