Here's a handy reference to the greek letters, including variants provided by LaTeX.

TeX versions are \symbol, HTML versions are &symbol;. You can right click and view source on this page to see the HTML versions.

$\alpha \beta \gamma \delta \epsilon \varepsilon \zeta \eta \theta \vartheta \iota \kappa \lambda \mu \nu \xi o\pi \varpi \rho \varrho \sigma \varsigma \tau \upsilon \phi \varphi \chi \psi \omega \Gamma \Delta \Theta \Lambda \Xi \Pi \Sigma \Upsilon \Phi \Psi \Omega$

$\alpha$ $\beta$ $\gamma$ $\delta$ $\epsilon$ $\varepsilon$ $\zeta$ $\eta$ $\theta$ $\vartheta$ $\iota$ $\kappa$ $\lambda$ $\mu$ $\nu$ $\xi$ $o$ $\pi$ $\varpi$ $\rho$ $\varrho$ $\sigma$ $\varsigma$ $\tau$ $\upsilon$ $\phi$ $\varphi$ $\chi$ $\psi$ $\omega$ $\Gamma$ $\Delta$ $\Theta$ $\Lambda$ $\Xi$ $\Pi$ $\Sigma$ $\Upsilon$ $\Phi$ $\Psi$ $\Omega$

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \begin{array}{lcr} \mbox{alpha} & \alpha \\ \mbox{beta} & \beta \\ \mbox{gamma} & \gamma \\ \mbox{delta} & \delta \\ \mbox{epsilon} & \epsilon \\ \mbox{varepsilon} & \varepsilon \\ \mbox{zeta} & \zeta \\ \mbox{eta} & \eta \\ \mbox{theta} & \theta \\ \mbox{vartheta} & \vartheta \\ \mbox{iota} & \iota \\ \mbox{kappa} & \kappa \\ \mbox{lambda} & \lambda \\ \mbox{mu} & \mu \\ \mbox{nu} & \nu \\ \mbox{xi} & \xi \\ \mbox{o} & o \\ \mbox{pi} & \pi \\ \mbox{varpi} & \varpi \\ \mbox{rho} & \rho \\ \mbox{varrho} & \varrho \\ \mbox{sigma} & \sigma \\ \mbox{varsigma} & \varsigma \\ \mbox{tau} & \tau \\ \mbox{upsilon} & \upsilon \\ \mbox{phi} & \phi \\ \mbox{varphi} & \varphi \\ \mbox{chi} & \chi \\ \mbox{psi} & \psi \\ \mbox{omega} & \omega \end{array} }

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \begin{array}{lcr} \mbox{Gamma} & \Gamma \\ \mbox{Delta} & \Delta \\ \mbox{Theta} & \Theta \\ \mbox{Lambda} & \Lambda \\ \mbox{Xi} & \Xi \\ \mbox{Pi} & \Pi \\ \mbox{Sigma} & \Sigma \\ \mbox{Upsilon} & \Upsilon \\ \mbox{Phi} & \Phi \\ \mbox{Psi} & \Psi \\ \mbox{Omega} & \Omega \end{array} }