Pratley Wonderfix is a flexible polyurethane 2 part adhesive. cures flexible, and sticks well to most things, aside from things that are typically hard to glue, like PTFE, some nylons, certain PET plastics and the like. Does well on PCB, metals, glass and especially rubber.
Otherwise for a general purpose single part polyurethane sealer try Sika Pro 2 HP, which is available worldwide. Drawbacks are cleaning once cured ( grind it off), it takes a while to cure in thick layers ( oxygen curing) and it will stick to everything around if you get it on by accident. Most common use is to make joins in concrete, and to put piping into ponds and tanks. will cure underwater, but is toxic to fish while curing from the isocyanate given off. Available in black, white and IIRC grey and brown. I use it for plumbing, and have used it to put window glazing in as well. Seal a toilet bowl to a pipe with this and the only way to remove is to put a new bowl in along with the pipe.