Hmmm.
Well . . .
I like certain Kershaw knives. I have a number of their old 3100 series (Japan). They're basically equivalent to the 110, 112, and 55. Sadly, the 3100 line is now made in PRC, and I have no idea what the QC is on those. I have Leeks and a few others. I like the Double Cross and Double Duty. Generally good knives, but the more they offshore, the less I go there.
I carry a Leatherman. Always. Everywhere. It's not a "favorite" particularly, but it's been the best at what it does, so it's always there.
I like Case. Case does some patterns (notably the Sod Busters) that Buck simply doesn't do. The Case Folding Hunter is a serious classic, as are the XX Changer, Mako, and Hammerhead. Their sodbusters are fine knives. Their Trapper, Muskrat, Peanut, and Pocket Hunter are excellent. I guess what's missing there is a compact and comfortable locking folder. No equivalent to the Vantage, for example. I actually prefer their "toothpick" style of main clip blade on their stockman. Very like the old Buck 313 Muskrat (can we bring that back, please?).
I also have a serious fondness for Swedish blades. The EKA line of folders is just superb. The Swede 92 is a no-foolin' lockback folder that's just as happy in the kitchen as it is outdoors. I'm glad I got a few while they were still in production. Their folding fillet knives? Great. The Nordic T8? Really good handle ergos, nice flat grind. The Swede 88 and its sibling, the Swede S8 are great compact lockbacks with generous but flat handles -- excellent for pocket carry and outdoor use. The classic Mora blades and their Norwegian & Finnish relatives are hard to beat no matter who you are.
If I look among the Bucks that are strewn across my table, and pick among them the others that get significant EDC time, I find that Case Sod Busters and the Case Medium Stockman are frequent pocket guests. The EKA folders get about the same amount of pocket time. It's been a while since I carried a Kershaw, although I'm not really sure why.
So I guess it's between Case and EKA for folders, and Mora, Järvenpää, Marttiini for fixed blades.
I would just be tickled to death if Buck wanted to do a line of Puukko knives.
There are only a few patterns that I use that Buck doesn't make. Sodbusters and Puukkos and Scandi grind folders are at the top of that list.