Is there a better upcoming album release calendar than Metacritic's?

If so, what is it?

I'd especially be interested in one that includes more underground/smaller label releases.

Insound used to have a fairly great one. Not sure what happened there, but it's gone.

This isn't quite what you're asking for but it's worth keeping an eye on for mainstream stuff: http://www.pauseandplay.com/

(Brainwashed had a kick-ass regular list once upon a time but that's over it looks like.)

http://www.pauseandplay.com/news/on-the-cd-front/

bookmarked

http://www.thefourohfive.com/page/upcoming-album-releases is useful too

Not a calendar, but a site's fave upcoming releases, mostly all indie-rock

http://consequenceofsound.net/2015/01/the-50-most-anticipated-albums-of-2015/full-post/

(Brainwashed had a kick-ass regular list once upon a time but that's over it looks like.)

They still do it, sort of
http://brainwashed.com/index.php?option=com_content&view=category&id=23:release-dates&Itemid=95

http://pitchfork.com/news/57757-the-pitchfork-guide-to-upcoming-releases-winter-2015/

The end of the Aquarius list usually has a decent amount (it looks shorter than usual this time, though):

http://www.aquariusrecords.org/cat/newest.html

I also like Rate Your Music's customized upcoming releases list: it only lists upcoming releases by artists you've rated something by, but that of course involves having a Rate Your Music account, which I know not everyone is into.

I include Upcoming Releases whenever you do a List Search on my site. It's not all-inclusive, only stuff I'm interested in: http://fastnbulbous.com/list.php

All my other links to auto queries are broken because of stupid updates WordPress made. I need to hire a programmer to fix up my site one of these days.