Silicones are both adhesives and sealers. The work well in situations where
the bond might get wet. They work well on glass. They don't break down in
cold weather. Unfortunately they are very toxic. Many of them contain the
solvent tetrachloroethylene, which is a known carcinogenic (causes cancer).
to some plastics and rubbers, so it is a good idea to test
what you are about to glue.
Most come in a caulking tube and need to be applied with
an inexpensive caulking gun. (Goop doesn't need a gun.)
If you are going to be doing any but the smallest amount of sealing
a cauking gun is worth it.
They are usually available in clear and a variety of colors.