If you use Guix, you can get a great Guile Scheme REPL and auto-complete via Emacs and Guile Arei and Ares (by Andrew Tropin). Add guile-ares-rs package to your manifest.scm and you can then run the REPL process with:
guix shell -m manifest.scm -- guile \
-L lib -L . \
-c '((@ (ares server) run-nrepl-server))'
In Emacs you can install it with:
(use-package arei :ensure (:host github :repo "abcdw/emacs-arei" :branch "master") :demand t) (use-package sesman :ensure (:host github :repo "vspinu/sesman" :branch "master") :demand t)
And then run arei.