In Abu Dhabi:
Middle East Exhibition — this place is fun to browse as they have a good amount of used electronic parts like speakers, etc.
Al Dhafra Electronics — our-main go-to here in town for electronic components and tools
Manora Trading — another fine shop with components and tools (not far from Dhafra on Electra Street
Skyway Trading (electrical enclosures) — this shop is good for plastic junction boxes of different sizes and shapes, quite nice for project enclosures.