> monad transformers for combining multiple effects.

This is a Haskell problem, not the fundamental one.

doFiles::forall e. Eff (fs::FS, console::CONSOLE|e) Unit
doHttp::forall e. Eff (http::HTTP, console::CONSOLE|e) Unit

doStuff::forall e. Eff (fs::FS, console::CONSOLE, http::HTTP|e) Unit
doFiles <<< doHTTP

You can also handle effect, which means you remove the effect from the row and once you get to the Eff () you can runPure and transform the effectful computation into the pure one. Bingo.