基于这个被接受的答案，Ubuntu 中安装的字体应该可供 fontspec 使用。
这是双子座投影仪主题：
% Gemini theme
% https://github.com/anishathalye/gemini
% ====================
% Dependencies
% ====================
\RequirePackage{exscale}
\RequirePackage{ragged2e}
\RequirePackage{changepage}
\RequirePackage{fontspec}
% ====================
% Fonts
% ====================
\newfontfamily\Raleway[Ligatures=TeX]{Raleway}
\newfontfamily\Lato[Ligatures=TeX]{Lato}
\usefonttheme{professionalfonts}
请注意，Raleway 和 Lato 似乎都已安装：
me@s2:~/code/pcquery_poster$ fc-list|grep Raleway
/usr/share/fonts/truetype/raleway/Raleway-ExtraBoldItalic.ttf: Raleway,Raleway ExtraBold:style=ExtraBold Italic,Italic
/usr/share/fonts/truetype/raleway/Raleway-SemiBoldItalic.ttf: Raleway,Raleway SemiBold:style=SemiBold Italic,Italic
/usr/share/fonts/truetype/raleway/Raleway-ExtraBold.ttf: Raleway,Raleway ExtraBold:style=ExtraBold,Regular
/usr/share/fonts/truetype/raleway/Raleway-ExtraLightItalic.ttf: Raleway,Raleway ExtraLight:style=ExtraLight Italic,Italic
/usr/share/fonts/truetype/raleway/Raleway-Bold.ttf: Raleway:style=Bold
/usr/share/fonts/truetype/raleway/Raleway-MediumItalic.ttf: Raleway,Raleway Medium:style=Medium Italic,Italic
/usr/share/fonts/truetype/raleway/Raleway-BlackItalic.ttf: Raleway,Raleway Black:style=Black Italic,Italic
/usr/share/fonts/truetype/raleway/Raleway-Black.ttf: Raleway,Raleway Black:style=Black,Regular
/usr/share/fonts/truetype/raleway/Raleway-Medium.ttf: Raleway,Raleway Medium:style=Medium,Regular
/usr/share/fonts/truetype/raleway/Raleway-BoldItalic.ttf: Raleway:style=Bold Italic
/usr/share/fonts/truetype/raleway/Raleway-ExtraLight.ttf: Raleway,Raleway ExtraLight:style=ExtraLight,Regular
/usr/share/fonts/truetype/raleway/Raleway-Light.ttf: Raleway,Raleway Light:style=Light,Regular
/usr/share/fonts/truetype/raleway/Raleway-Regular.ttf: Raleway:style=Regular
/usr/share/fonts/truetype/raleway/Raleway-Thin.ttf: Raleway,Raleway Thin:style=Thin,Regular
/usr/share/fonts/truetype/raleway/Raleway-LightItalic.ttf: Raleway,Raleway Light:style=Light Italic,Italic
/usr/share/fonts/truetype/raleway/Raleway-ThinItalic.ttf: Raleway,Raleway Thin:style=Thin Italic,Italic
/usr/share/fonts/truetype/raleway/Raleway-Italic.ttf: Raleway:style=Italic
/usr/share/fonts/truetype/raleway/Raleway-SemiBold.ttf: Raleway,Raleway SemiBold:style=SemiBold,Regular
me@s2:~/code/pcquery_poster$ fc-list|grep Lato
/usr/share/fonts/truetype/lato/Lato-Medium.ttf: Lato,Lato Medium:style=Medium,Regular
/usr/share/fonts/truetype/lato/Lato-SemiboldItalic.ttf: Lato,Lato Semibold:style=Semibold Italic,Italic
/usr/share/fonts/truetype/lato/Lato-LightItalic.ttf: Lato,Lato Light:style=Light Italic,Italic
/usr/share/fonts/truetype/lato/Lato-Italic.ttf: Lato:style=Italic
/usr/share/fonts/truetype/lato/Lato-MediumItalic.ttf: Lato,Lato Medium:style=Medium Italic,Italic
/usr/share/fonts/truetype/lato/Lato-Black.ttf: Lato,Lato Black:style=Black,Regular
/usr/share/fonts/truetype/lato/Lato-Light.ttf: Lato,Lato Light:style=Light,Regular
/usr/share/fonts/truetype/lato/Lato-Regular.ttf: Lato:style=Regular
/usr/share/fonts/truetype/lato/Lato-ThinItalic.ttf: Lato,Lato Thin:style=Thin Italic,Italic
/usr/share/fonts/truetype/lato/Lato-HairlineItalic.ttf: Lato,Lato Hairline:style=Hairline Italic,Italic
/usr/share/fonts/truetype/lato/Lato-Thin.ttf: Lato,Lato Thin:style=Thin,Regular
/usr/share/fonts/truetype/lato/Lato-BoldItalic.ttf: Lato:style=Bold Italic
/usr/share/fonts/truetype/lato/Lato-Bold.ttf: Lato:style=Bold
/usr/share/fonts/truetype/lato/Lato-Heavy.ttf: Lato,Lato Heavy:style=Heavy,Regular
/usr/share/fonts/truetype/lato/Lato-Semibold.ttf: Lato,Lato Semibold:style=Semibold,Regular
/usr/share/fonts/truetype/lato/Lato-HeavyItalic.ttf: Lato,Lato Heavy:style=Heavy Italic,Italic
/usr/share/fonts/truetype/lato/Lato-BlackItalic.ttf: Lato,Lato Black:style=Black Italic,Italic
/usr/share/fonts/truetype/lato/Lato-Hairline.ttf: Lato,Lato Hairline:style=Hairline,Regular
然而，当我尝试编译我的 beamer 海报时，我收到有关 latex 无法找到这些字体的错误：
Package: fontspec 2022/01/15 v2.8a Font selection for XeLaTeX and LuaLaTeX
(/usr/share/texlive/texmf-dist/tex/latex/fontspec/fontspec-xetex.sty
Package: fontspec-xetex 2022/01/15 v2.8a Font selection for XeLaTeX and LuaLaTeX
\l__fontspec_script_int=\count349
\l__fontspec_language_int=\count350
\l__fontspec_strnum_int=\count351
\l__fontspec_tmp_int=\count352
\l__fontspec_tmpa_int=\count353
\l__fontspec_tmpb_int=\count354
\l__fontspec_tmpc_int=\count355
\l__fontspec_em_int=\count356
\l__fontspec_emdef_int=\count357
\l__fontspec_strong_int=\count358
\l__fontspec_strongdef_int=\count359
\l__fontspec_tmpa_dim=\dimen285
\l__fontspec_tmpb_dim=\dimen286
\l__fontspec_tmpc_dim=\dimen287
(/usr/share/texlive/texmf-dist/tex/latex/base/fontenc.sty
Package: fontenc 2021/04/29 v2.0v Standard LaTeX package
) (/usr/share/texlive/texmf-dist/tex/latex/fontspec/fontspec.cfg)))
./beamerthemegemini.sty:18: Package fontspec Error: The font "Raleway" cannot be found.
For immediate help type H <return>.