netrw indeed can do case-insensitive sorting (which I suppose is what you want): Put the following into your ~/.vimrc
:
let g:netrw_sort_options = "i"
As the netrw file listing is a plain Vim buffer, you can quickly locate entries via the default /
search command. If you want a solution that filters the list of candidates as you type, you need a different plugin like FuzzyFinder or Command-T.