It took a little longer than planned due to a lack of SIM but I have finally unlocked all the technologies on DCity. This doesn't mean that I actually have the technology.
What it means is that there is a chance that my Research Center has a chance to discover the technology each day. Look at the technologies, I realize that I have none of the rarest ones having sold off a voice to skull card.
For the second most rare, I have two - Free Education which I feel is a must and the Bitcoin Fund which isn't as useful. I am curious to see what the Mining Operation card does. Apart from that, maybe an Advanced Training technology card is probably the only other one that I want.
When it comes to non-technology cards, I noticed that there is a new Lawyer card which is stackable and gives a tax refund. With taxes the way they are, might be worth looking into.