$$ \mathrm {\color{white}\colorbox{#3486e7}{\Large~Fonts~}} $$
$\mathtt {Old~Typewriter}$
$\mathsf {Sans~Serif}$
$\mathbb {BOARD~uppercase}$$\mathrm {Elégant}$
$\mathcal {By~hand}$
\\mathtt {Old~Typewriter}
\\mathsf {Sans~Serif}
\\mathbb {BOARD~uppercase}
\\mathrm {Elegant}
\\mathcal {By~hand}
$$ \mathrm {\color{white}\colorbox{#3486e7}{\Large~Couleurs~}} $$
$\colorbox{aquamarine}{abc}$
$\color{white}\colorbox{cadetblue}{abc}$
$\color{#f82094}{abc}$
$\color{red}\fbox {abc}$
$\color{#FFFFFF}\colorbox{#f82094}{---(~}\colorbox{#3486e7}{a|b|c}\colorbox{#1c2db9}{~)---}$
\\colorbox{aquamarine}{abc}
\\color{white}\\colorbox{cadetblue}{abc}
\\color{#f82094}{abc}
\\color{red}\\fbox {abc}
\\color{#FFFFFF}\\colorbox{#f82094}{---(~}\\colorbox{#3486e7}{a|b|c}\\colorbox{#1c2db9}{~)---}
$$ \mathrm {\color{white}\colorbox{#f82094}{\Large~Sizes~}} $$
$\tiny {Tiny}$
$\scriptsize Script~Size$
$\footnotesize Footnote$
$\small Small$
$\normalsize Normal$
$\large Large$
$\Large Large$
$\LARGE Large$
$\huge Huge$
$\Huge Huge$
\\tiny {Tiny}
\\scriptsize Script~Size
\\footnotesize Footnote
\\small Small
\\normalsize Normal
\\large large
\\Large Large
\\LARGE Large
\\huge Huge
\\Huge Huge
$$ \mathrm {\color{white}\colorbox{#1c2db9}{\Large~Decorations~}} $$
$\utilde{Wave}$
$\underrightarrow{Arrow~to~right~~~}$
$\underleftarrow{~~~Arrow~to~Left}$
$\underline{Underline}$
$\overline {Overline}$
$\undergroup{1}~~\undergroup{2}$
$\sout{~crossed~}$
$\xcancel{Cancel}$
$\mathbb{\color{3486e7} {\Huge D}}$ropcap
\\utilde{Wave}
\\underrightarrow{Arrow~to~right~~~}
\\underleftarrow{~~~Arrow~to~Left}
\\underline{Underline}
\\overline {Overline}
\\undergroup{~~1~~}~~\\undergroup{~~2~~}
\\sout{~crossed~}
\\xcancel{Cancel}
\\mathbb{\\color{3486e7} {\\Huge D}}
$\def\arraystretch{2}\begin{array}{c:c|c||c}{lines}&{between}&{some}&{words}\end{array}$
def\\arraystretch{2}\\begin{array}{c:c|c||c}{lignes}&{entre}&{les}&{mots}\\end{array}
$$
\mathrm {\color{white}\colorbox{#f82094}{\Huge~A~Huge~text~centered~with~a~full~size~math~block~}}
$$
\\mathrm {\\color{white}\\colorbox{#f82094}{\\Huge~~~A~Huge~text~centered~with~a~full~size~math~block~~~}}
$$
\mathrm {\color{1c2db9} \utilde{~A~centered~textwith~a~beautiful~wave~~~}}
$$
\\mathrm {\\color{1c2db9} \\utilde{~~~A~centered~text~~with~a~beautiful~wave~~~}}
$$
\mathrm {\color{3486e7} \fbox{~A~text~with~a~border~}}
$$
\\mathrm {\\color{3486e7} \\fbox{~~~A~text~with~a~border~~~}}
Source : https://notionthings.com/2021/01/23/advanced-notion-formatting-using-katex-expressions/