Having gone from a stock vim to a highly modified vim and back again, here are some plugins that I find really boost my productivity:

- neoterm, for opening a REPL in a split buffer and quickly sending chunks of lines to the REPL (https://github.com/kassio/neoterm)

- fzf for faster buffer and file navigation (https://github.com/junegunn/fzf.vim)

- vim fugitive for good git integration (https://github.com/tpope/vim-fugitive)

- some other tpope plugins (surround, unimpared, commentary, vinegar)