An EDC knife is a general utility knife. Rather than launch into Brand recommendations, I'll suggest knife features that work for doing a large list of diverse tasks cutting a broad variety of materials.
The blade shape that best accommodates everything is the drop point. It gives a fine enough point to dig out a splinter, but its obtuse enough to resist breaking off. That shape can vary some, but generally the blade in 3-4" class is somewhat a long triangle, with most of the taper out at the tip. Tantos don't allow much use of the blade near the tip, clip points are traditional, but don't allow letting the blade back coast against a underlying side and the blade cutting what's above, like box strapping, seat belts, or dressing a deer.
The blade grind is the profile from edge to back, the most visible part of the blade. Flat ground blades are more useful, and the #1 in food prep. Considering that the #1 experts in knife use - cooks and chefs - prefer it says something about the way it handles the wide variety of things we prepare, from rubbery liver or tough tomatoes, corn cobs, and chops, to spreading peanut butter on crackers. It takes more time, and is more expensive, to grind a full flat profile on a knife properly. When you see a grind line less than 3/4 of blade width, cutting becomes more difficult, as the swedge exerts high presssure at that transistion, creating friction and drag. It's a major indication the knife is actually a sharpened pry bar - not an EDC user - and that the maker has gone cheap. Blade grinds with multiple intersections are part of the art of blade design, but some use them to visually enhance the knife rather than make it a useful tool. They think their customers can provide that to them.
Blade openers are usually studs, discs, or holes. The assisted openers are of benefit to those with arthritis, otherwise healthy users can forgo them. They all work, the leverage point vs. the blade axis for that persons hand is the particular issue. The best thing to do is try them at a knife shop. It's completely individual.
Blade steels run from cheap to overkill, the midrange stainless will do. AUS8, ATS34/154CM, 440C, and even the newer Chinese steels from major makers do the job.
Locks are only important to those who misuse knives. They cut, and using the tip or back of the blade in a way that would fold up a slip joint knife is not cutting. The most prevalent lock in "one hand openers" is the liner lock invented - but not patented - by Mike Walker. Three important aspects make or break a good liner lock and make it reliable: It should be at least 1/2 the thickness of the blade at the lock ramp, the leaf length should be at least 3/4 blade length, and it should not be the same material as the blade. Short, thin liner leaf are prone to walking out of the lock and failing. Even $100 knife makers can get it wrong, and sometimes, they do follow the rules.
You can check it by trying to compress the blade and work it back and forth to see if the lock works out, but don't forget, YOUR FINGERS WILL BE IN THE WAY. Another method is to tap the back of the locked blade against something unmarking but firm, like a steering wheel or 2x4. It's called spinewhacking, and as a lock test method has a negative reputation from all the internet dweebs chopping concrete to prove how tough their sharpened prybars are. Don't take it too far - it's just an EDC knife.
Traditional back locks, button locks, and sliding pin or rollers are also used. The #1 law about knife locks is that they are all just simple mechanisms and will fail.
Grips are made from a variety of materials. Brass with natural grips in wood or stag antler flexes too much over a period of years, and will loosen up and crack. Aluminum or stainless is popular, but tends to appear in cheap knives, often with guady cutouts. Fiberglass reinforced nylon is common, and extensively used, but the cost of molds prohibit a lot of style changes. The Griptilian is a great example of doing it right, the 99c buncha knives in a jug at checkout lanes exactly what to avoid. G10 is a fiberglass sheet material that has to be cut and shaped, and what I recommend. It doesn't need liners like FRN, and makes for a thinner, lighter handle. Titanium is sometimes used, and generally expensive. It allows the maker to use that grip scale directly as the liner lock. They don't come cheap, but used titanium frame locks can come to trade in the $100 range.
Grip shapes run from the ridiculous, like the 1911 with too much straightness and one corner where it shouldn't be, to molded multifinger grooved monstrosities that prevent alternate grips or uses. Simple is better, the less curves overall works, with a gentle back arc, and a cutout for the lock.
Clips come in a variety of shapes, control the amount the knife protrudes from the pocket, and let the knife ride tip up or down. Claims can be made for both about how easy it may be to get out and opened, I've tried both. The one thing I find important is whether the hand is irritated reaching past the knife with multiple slots or knurling, and whether I trust the detent to keep the blade closed. Tip up is not my favorite in that regard.
Examples (not necessarily recommendations,) include:Spyderco Tenacious, Benchmade Vex, Boker Plus M type, Spyderco Endura, Emerson CQC6 and 7, CRKT M16 series. While seeming to lean toward tactical, they don't go too far, and aren't overly expensive. A hundred others could be mentioned - but at this time, only one will do, and that's going to be solved best by seeing and handling them.
Get thee to a knife retailer, but be warned: you can get tempted by the sirens near the rocks and wind up ruined. Don't ask how I know.
