MadQuilter

I go with gray.

sewingsuz

I also have been using grey a lot lately.

bearisgray

Gray or thAt smoky green.

Jane Quilter

I use gray alot. and I always use a neutral to piece. If in doubt, I stitch a sample piece, turn to the right side and pull/spread/stretch the seam open to see what you see. If it jumps out at you (think piecing with red), I would change it to a neutral less noticeable. (not that red is a neutral, I was just making an illustration)

joe'smom

I've started using up my older thread when piecing, regardless of the color of thread and fabric. If sewing black and white together, I think a medium neutral would be best.

JanieH

Neutral gray is my go-to color for this.

tessagin

I have a lot of grey thread for this reason. If hand quilting like big stitch I use matching thread.

klswift

When I am sewing 2 high contrast fabrics together, I try to plan to sew them all the same way (light on top). Doesn't matter on top thread (usually use a neutral) but I use the dark color in the bobbin. This is because I press the seam to the dark side and if a high contrast thread, there is a slight possibility of it showing thru. With a good quality fabric, this probably isn't a problem, but it is a habit I formed years and years ago and it works for me.

csknott

I use gray or a nutral for all my piecing regardless.

MissSongbird

I tend to use white for most of my piecing anyway, so I would say white.