Let’s see what I can come up with in physics and math:
Alpha: Looks like A. alpha: The Fine Structure Constant, a helium nucleus, angular acceleration, confidence level.
Beta: Looks like B. beta: An electron from nucleon decay
Gamma: The Affine Connection in Riemannian Geometry, the continuous generalization of the factorial. gamma: A high-energy photon, the relativistic dilation factor.
Delta: Change. delta: Variation, Kroneker’s symbol, the Dirac distribution.
Epsilon: Looks like E. epsilon: An arbitrarily small value, permitivity, electromotive force.
Zeta: Looks like Z. zeta: Difficult to draw (see xi).
Eta: Looks like H. eta: Minkowski metric
Theta: Time-reversal operator. theta: An angle
Iota: Looks like I. iota: I don’t know of anything.
Kappa: Looks like K. kappa: Imaginary wavenumber
Lambda: Lorentz transformation. lambda: Wavelength, eigenvalue, linear density
Mu: Looks like M. mu: Permeability, magnetic dipole moment, reduced mass, muon.
Nu: Looks like N. nu: Frequency, neutrino
Xi: Don’t know. xi: Difficult to draw (see zeta).
Omicron: Looks like O. omicron: looks like o
Pi: Product. pi: Circumfrence/diameter, parity operator, parallax, pion
Rho: Looks like P. rho: Space density (of charge, mass, or number), distance from axis.
Sigma: Sum. sigma: conductivity, area charge density, standard deviation.
Tau: Looks like T. tau: Torque, proper time, tauon.
Upsilon: Looks like Y. upsilon: I don’t know.
Phi: Electric potential, general scalar field. phi: An angle, eigenfunction.
Chi: Looks like X. chi: Susceptibility, deviation of fit.
Psi: Wavefunction. psi: an angle.
Omega: Ohm, an angle. omega: angular frequency.
Alpha, Beta, Epsilon, Zeta, Eta, Iota, Kappa, Mu, Nu, Omicron, omicron, Rho, Tau, and Upsilon are generally not used, as they resemble Latin letters. I don’t know of any standard uses for zeta, iota, Xi, xi, or upsilon, offhand.