Do you want full fenders, but not all of the time? If you have a folding bicycle or a racing bike this is likely. This webpage shows how I use wingnuts to make my fenders removable very quickly.
There are two areas where fenders connect to the bicycle. One is at the dropout where the stays connect. If you use recent ESGE/SKS fenders that came with a safety mechanism then you don't need to do anything here. Just pull the fender stay out of the plastic block. For most other fenders you can mount the bolts with the heads facing inwards. This makes for small studs that are permanently mounted to your dropouts. Place the fender stay over the bolt, then use a wingnut to secure it. On the rear dropout you might not have enough space between the small cog and the dropout for the head of a bolt. In these cases I use wingbolts and trim them to length.
The other connection point is where fender joins the seatstay, chainstay, or fork crown. Usually these aren't threaded. I make a stud by running a long bolt through and then securing it with a nut. When you mount the fender you just push the eyelet over the stud and secure it with a wingnut. You can see that I also cut out the top of this fenders eyelet so that I could slide it over the stud without completely removing the wingnut.
Using these techniques you can make almost any fender or rack mount with no tools.