I have a Chrome search engine of the form
https://%s.stackexchange.com/ that I use to quickly move between various SE sites (I find this more efficient than bumbling my way through the multicollider).
It would be nice if we could get aliases (like e.g.
https://stackoverflow.stackexchange.com/ as a redirect to https://stackoverflow.com/) for all the sites that have their own domain names. I believe that's just the Trilogy (SO, pt/ja/ru.SO, SU, SF) and Stack Apps (plus corresponding metas where they exist, plus Meta MathOverflow).
EDIT: Either I forgot to check MathOverflow when I originally posted this, or it's been added since then - https://mathoverflow.stackexchange.com/ redirects to https://mathoverflow.net/ now. However, https://mathoverflow.meta.stackexchange.com/ does not go anywhere.