well
simply the best...
of course there are many ...complex osc/mixers that are not the best
as we all know...
so question is the simpliest solution for fm osc/mixer?
any schematic or link ?
There is no "best" whatsoever.
What is best depends on the requirements you have:
price
complexity
size
power
endurance
...
These are antagonists. For example: usually low price and hihg power are mutually exclusive. A simple solution may result in poor signal quality. etc. etc.