A challenging SAO that was offered to me was the "Yo Dawg, I heard you like SAOs in your SAOs", which including some micro SAOs that were challenging to solder. That was an excuse for me to learn SMD soldering with solder paste, flux paste, and the heat gun I had.
links:
I didn't do a great job, but it worked, which is what mattered. The motherboard was easy to solder with a real soldering iron, but this micro SAO was the challenging one:
The micro SAO didn't really have clear indications on positive vs negative, so I had to test the board and LEDs to make sure they were in the correct direction:
They, I had to lay out the components:
Cover with solder paste and flux:
oh boy, not looking pretty :)
And after heat gun, things mostly went into place:
