JuliaNLSolvers easy to use solvers written in Julia for solving non-linear systems of equation and optimization problems
Optim.jl – maintainer of a widely used pure Julia numerical optimization suite (paper)
PlotThemes.jl – themes for the great plotting metapackage Plots.jl
QuantileRegression.jl – simple quantile regression package
JuliaLang – small contributions here and there