Text formating in Matplolib

\mathit{}: default (italic)
\mathrm{}: Roman (upright)
\mathtt{}: Typewriter (monospace)
\mathbf{}: bold
\mathbfit{}: bold italic
\mathcal{}: calligraphic
\mathsf{}: sans-serif

References:

Writing mathematical expressions — Matplotlib 3.8.3 documentation