I'm not sure this is what you're looking for, but maybe you could try `fzf` and `fzf.vim`.

`fzf` can be downloaded and installed from [github][1], and `fzf.vim` [as well][2].

If you use `vim-plug` as a plugin manager, all you should have to do to install them, would be to add these lines in your `vimrc`:

    Plug 'junegunn/fzf', { 'dir': '~/.fzf', 'do': './install --all' }
    Plug 'junegunn/fzf.vim'

... somewhere between the lines:

    call plug#begin('~/.vim/plugged')

and:

    call plug#end()

Then execute `:PlugInstall`.

----------

Among various commands and mappings provided by `fzf.vim` (whose only purpose seems to be to install mappings and commands asking `fzf` to fuzzy search through predefined sources), there is the command `:Ag`.

To be able to use it, you need to install the shell command [ag][3]. On debian based distributions, it can be done with the following command:

    apt-get install silversearcher-ag

The project on github explains how to install it on MacOS:

    brew install the_silver_searcher

`:Ag` allows you to fuzzy search a pattern in the files of the current directory (the one displayed when you type `:pwd`). The matches are updated after every keystroke.

You can cycle forward and backward through the matches with `C-n` and `C-p`.  
You can select the current match and move forward/backward with `Tab`/`S-Tab`.  
You can select all the matches with `M-a`, and deselect them with `M-d`.  

If you select one or several matches, they will populate the quickfix list from which you'll be able to navigate through them with default Vim commands / mappings, such as `:cnext` and `:cprevious`.

[![enter image description here][4]][4]

If you want to add a prefix to all the commands installed by `fzf.vim`, you can add this in your `vimrc`:

    let g:fzf_command_prefix = 'your_prefix'

I use `Fzf` as a prefix, that's why I didn't type `:Ag` but `:FzfAg`.


  [1]: https://github.com/junegunn/fzf
  [2]: https://github.com/junegunn/fzf.vim
  [3]: https://github.com/ggreer/the_silver_searcher
  [4]: https://i.sstatic.net/XlTIQ.gif