Man I loved my Blackout. Was my sole EDC for 6 or 7 years at one point. Shame they’ve discontinued it (the Whirlwind just isn’t the same).
I agree though, throw in a Spyderco. My vote is a Manix if you can deal with how wide it rides in the pocket.
Your idea of a Guardian 3 is a good option, if you can get away with it at work. But you can always get a pocket sheath for it, so it’s a bit more discreet.
Those just happen to be my two primary EDCs, so I’m a bit biased.
Other good options....
Everyone should EDC a Leek at least once. Super thin and slicy, and light enough to wear in sweats or basketball shorts. Not a super, hard use blade, but a great all-a-rounder if most of your use is fairly light.
Another vote for the Ontario Rat. Just a great budget beater you can rely on.
Steel Will Modus. Again, another budget friendly knife that punches well above its weight. It’s become one of my workhorses, as I’m not worried about abusing a $50 knife... and it just keeps begging for more.
Can’t help you too much with higher priced folder, as they’re beyond my normal budget.