Similarly, for packages for optimization in Julia, we go to the web page at https://pkg.julialang.org/. Then, we can search these packages by using the keyword optimization; see one package called JuMP in this screenshot:
There are about 45 matches for the keyword optimization. To save space, we won't show the other packages. This web page, titled Optimization packages for Julia language, might be quite useful: http://www.juliaopt.org/.