If we're not counting the Demon Lord herself, the most powerful Monsters are the Lilims. Following them are Baphomets if I'm remembering right.
As far as the order side goes, the best humanity has to offer are heroes, the ones we've seen so far aren't all that impressive. You know, the whole being corrupted by one lilim and her buddies dealio. So as far we know so far, not really.
(I'm still hoping for Seraphs and Archangels to make up the difference, I have the sinking feeling I may be waiting for a while.)
For comparison to normal people, especially noteworthy Heroes are stated in World Guide 3 to have strength equivalent to a 1,000 normal soldiers. Such heroes are themselves more powerful than most monsters, but it means that hight ier monsters have power equivalent to or greater than that. Other noteworthy examples include a mention of how a single high tier monster can destroy a town (its not clear if this is meant to mean they can nuke it in one attack or not).
Power also has different meanings though. For instance baphomets are the strongest monsters when it comes to physical strength (though they are also very accomplished with magic, there are monsters that exceed them, such as lilims), and dragons are not far behind them in strength. Of course these likely speak of averages too, there are likely some dragons that are stronger than some baphomets, and then one has to consider exceptional individuals that exists for most races and are far more powerful than average (like the shirokuto witches who are noted to be more powerful sorcerers than average baphomets).
When it comes to races with the most powerful magic, some notable examples are echidnas and nine tailed foxes (youkos and inaris), the latter of which are noted to have power greater than a low rank god (there are low rank, mid rank, and high rank gods in the setting). And the Queen of Hearts is noted to have more power when it comes to magic than any of her sister lilims, making her probably the most powerful monster when it comes to magic (outside of her Lilith of course). If I recall right the only monster explicitly noted to have the power of a high rank god or higher (that wasn't originally a god to begin with) is the Mamono Lord Lilith (albeit the context of that statement was when she was fighting alongside her husband, she may not have as much power on her own, though on the other hand she is more powerful now than she was back then).
And on that note, Lilith being the most powerful monster, and her husband the most powerful human/incubus, almost certainly applies in the current setting just as it did a thousand years ago. But even here this may apply only in general terms, with some other individuals being better than even them at certain things.