I'll begin with base coats. They're incredibly important but if you've never used one, you won't know what you're missing. For a while I didn't use one but a good base coat sets the stage for a good manicure. They create an even foundation for your nail polish to build on. There are more brands of base coats than I could ever even name but these are the ones I've used and like. Not every base coat I use is pictures; just the ones I found effective.
-Orly Nail Armor
-NailTek Foundation II
I like the Nail Armor and NailTek for its ridge fillers. I don't always need that because I do buff from time to time which helps even out the nail but too much buffing will make them weak, so be mindful of that. Both of these leave a matte finish on your nails, but Nail Armor has little fibers in it.
CND leaves a shiny finish on your nails and I've personally noticed once it gets down to about where the photo is showing, the color concentrates and *is* noticeable on your bare nail. It took me a lot of trial and error to find base coats I like, and right now my preference is CND Stickey, but that could change. Prepping the nail by swiping it over with acetone or alcohol helps adhere the base coats better as it removes your natural oils.
-Out the Door 2 fl oz
-Sally Hansen Insta-Dri Anti-Chip
-Out the Door .5 fl oz
-NYC Grand Central Station
At this point, as you can see, Out the Door is my favorite quick try top coat; I have lots of it. It used to be the Sally Hansen until I had two bottles that cause bubbling, which was strange because I used it for a long time and then randomly it stopped agreeing with me. I still use it from time to time without much trouble.
I'm sure you've all heard about Seche Vite and might be wondering why isn't on my list. I tried it, and it's just OK for me. I don't like that you have to apply it on WET nail polish (otherwise it causes the polish to "shrink" and pull away from the tips of your nails). I do my nails at a snails pace and like being able to put topcoat on when I'm ready for it. I find lots of other quick dry top coats to be just as shiny without the inconvenience or price. For example, the 2 fl. oz. bottle of OTD was only $6 online. The bottom line for me on OTD is it's cheap, effective, super quick drying and plenty shiny.
The NYC top coat isn't really even a top coat but works well as one. It's just a clear polish that is of a quick dry line but it's the cheapest you can get ($2) and works well, dries quick and supposedly (I haven't tested this out yet) doesn't kill holos! A lot of holos you can't wear top coats on because it dramatically dulls their effect.
A good top coat is important as it is the outermost layer of your manicure, so it needs to hold up against whatever you're going to put it through. There are tons available, I get OTD from Harmons or online but many other quality ones are available literally everywhere. It's going to take you a while to find your perfect combination, I'm still not sure if I have. I think OTD will be my topcoat of choice and I do love the CND but I'm convinced there has got to be better out there!