Fixed or folder?
I assume a folder, since you're rocking a rat currently. For that, I think the first place to look is still cold steel. While there warranty has gone to crap, and they may start slipping at any time, so far the build quality is still there.
The voyager models are great; I've had one for decades now. Multiples, of various sizes. They're really hard to beat on a bang for buck level.
They've got other tanto models too, but I err on the voyager still.
And, tbh, they're kinda great in fixed blades too. Probably the best bet is the tanto version of the srk. Tough as hell, affordable, and has the best hand feel outside of custom knives that I've ever had on a tanto.
However, there's other brands aplenty. I recently had a chance to play with a cjrb bellona. Maybe not the toughest out there, but the blade grind made it really nice. It's similar to the cold steel kind of grind, with the secondary tip having a curve more like traditional tanto.
If you hunt for sales, the benchmade bailout is decent. Good steel overall, good hand feel, but a wee bit over priced imo. But you can usually find used at more reasonable prices.
The civivi brazen is okay, if you like button locks. Otherwise, I'm not a fan personally. Mind you, it's more of a preference thing, the quality is fine, I just favor other locks, and the balance is off for my tastes.
Crkt has the m16 tanto that's very popular, and for good reason. However, you gotta be aware that their folding knives have spotty QC, so you might have to deal with exchanges to get a great one. The big plus is that if you're looking for serrated, the big scallops they have as an option are unique, nobody else does them.
Kabar makes a respectable fixed blade tanto. Not the best when it comes to toughness, but pretty damn good.
Kershaw has the emerson branded cqc tanto that's not my preference, but is a reliable option overall.
I'm kinda struggling to pull more out of my head. Tanto was the first kind of knife I ever trained with, so they have a special place in my heart. Which means I've handled or used so many over the years that they bleed together.
Anyway, serrations. You can find plenty of tantos with them. If you like serrations, you won't find that the tanto pattern suffers from having them the way very curved blades can. I don't personally like full serrations, and only like half serrated blades on a very limited number of knives (my secondary is a half serrated, but I only own maybe four that have them at this point), but that's preference. Serrated knives have benefits and drawbacks like plain edges do.
Now, with that in mind, if you're interested in opinions about tanto and knives in general, keep reading. Otherwise just skip the rest.
Tanto have some nice benefits, and a few drawbacks. When it comes to your primary carry knife, you want to consider that a tanto is not going to usually have a belly worth mentioning. It's a trade-off. You lose the easy slicing of a belly, and gain the extra penetration a tanto point can give. You also swap out easier sharpening on a knife like the rat for a more acute edge that may or may not give you much in exchange. I don't have any issues sharpening tanto, but some folks do. But the grinds on most production tantos are super acute, so you can get extra slicy slice, it just isn't always going to be ideal since different companies and different steels can make that a good or bad thing.
As much as I love tantos, neither of my daily carry knives are tanto. I used to carry my xl voyager everywhere, but once I got my benchmade 710 back when they first came out, it slowly took over my pocket. I've come to prefer the versatility of a curved tip more. That belly just does a wider range of tasks at a similar level of capability, whereas tanto points are all over the place in what tasks they do reliably well.
My real advice is to pick up a super cheap tanto and carry it along with your current knife for a week or two. Any time you're using a knife, switch between them, see what really works well for you. Then start looking for your new knife with what you learned in mind. You can usually grab a cheap s&w tanto and expect it to hold an edge for a week or two of light duty, long enough to get an idea of how the tip type is going to fit your needs.