Mass-effect – Which reaper ground forces derive from which races

It's fairly clear that some forms of the reaper ground forces derive from other races – for example Husks were once Human and Banshees were once Asari, and there are several others that seem fairly obvious.

Others are less so. The Brute, for example, immediately makes me think Krogran because of the size and strength, but the head isn't Krogran-like, which doesn't seem to conform to the "looks like a corrupted version of the species" pattern followed else where.

So, I'd like a full list of which of the reaper ground forces have been derived from which races.