1. polyester sewing thread
2. heavy weight top stitching thread
3. upholstery thread
4. stretch thread
5. woolly nylon
Let's break it down for the application I generally use each thread.
1. For all my general sewing I use a polyester thread. I don't always use Mettler. If I need to buy an unusual color that may only get used once I buy the cheapo thread from my craft store.
2. I love using this thread for hemming jeans. I'm a shorty and I always have to hem jeans. The Gutermann Mara coarse comes in a few shades of golden that closely match ready to wear denim. This black I used on my super duper favorite Hudson skinny jeans and you could never tell that I had to chop off a good four inches from the bottom.
3. I don't do upholstery but I really like the way this thread works with a leather sewing needle when making leather baby booties. There isn't a huge selection of colors, but I always find a good match for the leather I'm working with.
4. I love the Maxi-Lock stretch for sewing with knits. I use it on my serger (three thread option). I also use it in the bobbin of my sewing machine. So far I haven't encountered any problems and I really like the added stretch in my seams.
5. I use woolly nylon in underwear and swimsuit sewing. I've actually only made one swimsuit for Luca and it didn't fit really well so I'm hoping this Summer I can try again with better luck. I have used this thread for hemming store bought active wear (gym pants).
So there it is. The only other thread I keep at home is embroidery floss which I ardently collect yet rarely use.