can i sell normal map.. of a font?

I think it's the same as with any other copyrighted item. You need to see what is the license of the fonts in question. If it's in public domain, then you can sell derivative work (in this case normal map baked from font) without restrictions. If it has commercial license, then you can try to aquire owner's permission, or try to sell the normal map at your own risk with editorial license.

I think Garamond typeface design belongs to public space (means your free do do whatever), its a sixteenth century design and original copyright typically ends 70 years after original author has passed away.

Corbel I would probably avoid that one,

Fenwick Woodtype is set to free for commercial use (but not specifically mention it belongs to public space), disclaimers on the countless sites that provide it suggest they take minimal responsibility on what users donate or upload, so kind of remains an open question. Notice however there is no link to be found on a commercial version?

Personally, I would consider it safe to move forward on Garmond and Fenwick Woodtype.

My opinion: typeface made as normal map isn't the same as source font. Here is few reasons:
1. In my job I'm using different fonts. And I can say -- in 99% of all cases I need to adapt typeface to my own vision or needs. I'm don't using font editors and have enough time for rework letters (point by point, curve by curve). So source font is just reference. I don't see any rational reasons to count my job as illegal.
2. If somebody uses some font for 3D, it's also not the same as using this font in text documents, PDF's, books etc... Because quality result demands some amount of work and changes the source look (extruding and viewing to extruded object from different points of view gives different look of letters than on a flat "paper"). Also for good result usually needed beveling, stretching, bending and/or other operations.

But it's just my opinion, because we are living in very interesting world where rules not logic but reach and power (KAPYTALYSM :)))))... For example Richemont SA holding company has patent for the look of broken circle (or arc) just for using it to fight with anybody who offers something that looks more or less similar to Cartiers "juste en clou" items ("bent nail" rings, bangles etc.)