Github で ch_open とか job_start で検索をかけて引っかかってきたのの簡単なまとめ．そういうわけなのでいろいろ抜けがあると思います（ので編集リクエストとか投げていただければ喜びます）．またあれば +job 使うけど必須でないのも入っています．
- miyakogi/flyjedi.vim: Asynchronous Jedi auto-completion plugin for vim, using job and channel feature
- miyakogi/livemark.vim: Real time markdown preview plugin for vim
- miyakogi/vim-quickrun-job: job runner module for vim-quickrun
- mattn/vim-soundcloud
- mattn/vim-terminal
- aiya000/aref-web.vim: aref-web.vim can open web dictionaries on the vim async.
- bbchung/clighter8: VIM 8 plugin to improve c-family development environment based on Clang
- chemzqm/macdown.vim: Live preview markdown in Chrome using applescript
- eagletmt/neco-ghc: A completion plugin for Haskell, using ghc-mod
- fourjay/vim-keeper: Integrate documentation search into vim
- jsfaint/gen_tags.vim: A simple plugin generate ctags and gtags database for vim.
- metakirby5/codi.vim: The interactive scratchpad for hackers.
- kana/vim-pixivision: P <P
- mhinz/vim-grepper: Helps you win at grep.
- nhooyr/fasd.vim: fasd plugin for vim!
- osyo-manga/vim-agrep: Async grep.
- prabirshrestha/async.vim: normalize async job control api for vim and neovim
- ramele/agrep: Asynchronous grep plugin for Vim
- runoshun/tscompletejob: Vim plugin for typescript code complete
- ShadowKyogre/vim-wailing: Have vim yell at you when you aren't typing
- Shougo/dein.vim: Dark powered Vim/Neovim plugin manager
- thinca/vim-quickrun: Run commands quickly.
- tyru/jobby.vim: Simple process management plugin in Vim
- wincent/ferret: Enhanced multi-file search for Vim
検索系とプレビュー系が多いように思います．これからしばらくかけてプラグイン界がちょっとずつ塗り替わっていくのかなあとおもってちょっと楽しみ．
なお，+job や +channel と外部コマンドの連携については mattn/slckの readme やBig Sky :: Vim の channel を使って非同期 twitter タイムラインも参考になります．