I’ve found some really curly grain wood on trees that grew on hillsides and out in the open where the wind battered them.
Sometimes, depending on species, you can tell that the lean or tilt of the tree will likely give it I nee character, or sometimes large limbs have compressed wood under them at the union from the weight. I see it all the time with older maples, not saying it's definitely curly inside but there are clues sometines.
A trained eye can see some of these patterns with bark on. In my opinion, it’s worth stripping some bark to inspect for wavy grain if you have the opportunity (mainly maple). It can be very valuable. I have two pieces left from that tree. Hoping to turn something, someday.