STIX Math: 𝑥
XITS Math: 𝑥
Latin Modern Math: 𝑥
Neo Euler: 𝑥
TeX Gyre Pagella Math: 𝑥
TeX Gyre Termes Math: 𝑥
TeX Gyre Bonum Math: 𝑥
Asana Math: 𝑥