It seems that the rest of the minuscules are at U+1d44e ..., but the h, which is called Planck's constant, is not used for h. I got this impression from replacing all these glyphs and observing the expected result except in the case of h.
It’s ℎ (U+210E), in a different block than you checked. Here’s a useful reference.
Note that ISO style says to typeset constants upright, which would be \symup{h} or \mathrm{h}. There is also an upright ħ (U+0127) distinct from ℏ (U+210F). However, this does not appear to be common practice in mathematical physics.
h, see en.wikipedia.org/wiki/Mathematical_Alphanumeric_Symbols or unicode.org/charts/PDF/U1D400.pdf. It belongs to the Letterlike Symbols with codepoint U+210E. However I'm not sure how on-topic for this site this question is. – campa Mar 1 at 10:04