Hand quilting thread should be kept separate from machine quilting thread. Most brands coat the hand quilting thread and most that have 'quilting' written on them should be regarded as such. If it is labelled 'machine quilting' it is OK and Mettler brand is OK in machine. The other types will leave a residue in your tension discs.
Any strong thread can be used for quilting - the largest size that will go through the top needle is number 12 - but you can put thicker weight in the bobbin and sew the quilt upside down if you want some decorative stitches."Purists" will say you only use cotton and nothing else - however, many successful quilters use a variety of thread. As for colour, I always have Black,White, Grey, Maroon and Brown in my stash, as Blue can always be sewn with Grey if I have to 'make do'.