The Latin Modern Math and TeX Gyre Math support projects are complete. Together, these fonts provide a total of 5 fonts for typesetting mathematics, all produced by the GUST e-foundry. Details can be found here.
That page lists an additional six fonts, produced by other foundries, which support the mathematics opentype extension, including 3 available from CTAN:
- Asana Math;
- Stix Math (v.2 expected 2016-12-31 according to barbara beeton;
- Xits Math (contains a bold version);
and 3 proprietary:
- Cambria Math;
- Lucida Math (contains a demi bold version);
- Minion Math by Johannes Küster (contains a bold version).
GUST also provide this comparison document which covers all of the above fonts except for Minion Math.
That information is dated May 2014. What about new fonts? How can you evaluate their suitability?
- I wrote this answer a while back to explain why a particular font combination did not work with
unicode-math
. In that answer, I compared that font combination with Latin Modern Math, which provides proper support. You can use my answer to assess the suitability of other fonts for use with unicode-math
since I explain, basically, what a font needs in order to support typesetting maths using the interface this package provides. (The answer is: quite a lot.)
EDIT
Here's a mini-demo of the 5 maths fonts provided by GUST:

\documentclass{article}
\usepackage{amsmath}
\usepackage{unicode-math}
\NewDocumentCommand \testme { o }{%
\IfValueT{#1}{%
\setmainfont{TeX Gyre #1}%
\setmathfont{TeX Gyre #1 Math}%
TeX Gyre #1 \& TeX Gyre #1 Math:
}%
\begin{align*}
p(D_k/T) & = \frac{p(T/D_k) p(D_k)}{p(T)} \\
& = \frac{p(T/D_k) p(D_k)}{ \sum_{i=1}^n p(T/D_i) p(D_i)} & \text{where } \sum_{i=1}^n p(D_i) = 1 \\
\end{align*}%
}
\begin{document}
Latin Modern Roman \& Latin Modern Math:
\testme
\testme[Bonum]
\testme[Pagella]
\testme[Schola]
\testme[Termes]
\end{document}