If you have a spare hour or 2, you can always run around the main map and collect quite a few bits of yellow division tech.
I did just over half the map, picking up the all the remaining collectibles and hit every single crafting box on the way. Took me about 2 hours, but I also found a lot of superior weapon crates and standard gear that I had missed.
This is all the yellow division tech I found yesterday.
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Those are not yellow division tech, that's high end Electronics you picked up, Div tech is the bottom one..