I'm a bit brain-fried, so my contribution may not seem very cohesive. Plus, I admit, I tend to love older music more so than the "latest hits," so some of this stuff may seem outdated, but IMO, if your choir hasn't sung it, then it's new.
Off the top of my head:
More than Anything by Lamar Campbell. People use this as a P&W song, but it is a GREAT choir song.
God Specializes James Hall's version. Not super slow, but has a nice slow to medium tempo.
Perfect Peace Marvin Sapp's version.
Things Will Work Out by Ricky Dillard. Not super slow, but slow-to-medium. Powerful song.
For the Good of Them by Milton Brunson. Oldie but goodie. A classic that never goes out of style.
For Every Mountain by Kurt Carr...
Changed by Tremaine Hawkins... another classic.
When We Get Over There by Hezekiah Walker
It Shall Come to Pass by Hezekiah Walker
He's Preparing Me by Ernest Davis and Wilmington-Chester
You know the more I think about it, the more I'm feeling like you probably have taught/sung many of these songs already. Maybe you should consider resurrecting some of the slow songs your choir already knows and bring them back. Nothing like a nice walk down memory lane every once in a while.
Maybe VT can help you with the more recent material.... lol. I'm an oldhead.
