Pick up a copy of Expert Card Technique. The table on contents will serve your purpose. Card College has a more modern teaching technique, but for a list of sleights Expert Card Technique is a less expensive method.
You can view the table of contents via this link via the Preview functionality of google books. It's not really practical to try and list here "all the important techniques in card magic that if learned you can perform almost any card trick", but the above will come close. Again, please note there are better versions of the techniques in more modern works, but the basic list is still valid and the is simplest solution to what you are asking.
A control to the top, a control to the bottom, a false shuffle, a false cut, a force, a steal, a palm, and a switch. You can probably create a version of nearly any card trick out there with that list.
The specific techniques aren't actually that important, whatever works best for you is what you'll end up settling into. Most professionals, as far as I can tell, don't actually use a huge range of sleights regularly. This belief is enforced when you read a bunch of books - it's largely all the same techniques just used with unique presentations.
That being said I see nothing wrong with practicing a large variety of sleights as long as the ones used in performance are kept to performance proficiency. There are several sleights I practice semi-regularly that I not only have never used in a performance, I have no intention of doing so. I practice them because they're fun. And keeping things fun is how you avoid burn out.
Now here's the catch - in order to find the sleights that work best for you, you're going to have to try a few different ones. Which means reading some books, watching videos, etc. Learning magic is an investment.
The most important thing, I think, to keep in mind is that consistency is far more deceptive than the fanciest or most difficult moves out there. So when choosing which sleights to use, it's important to make sure all of your actions are consistent throughout the performance. What I mean by that is that you want all of your actions throughout an entire performance to seem like they all go together. Mixing in a flourishy false cut for no reason other than it looks neat, when the rest of the performance has been fairly straight forward card handling, would throw up unconscious flags in the audience's mind.
Counts, Cuts, Moves and Subtleties by Jerry Mentzer is another inexpensive book that lays out many moves for you.
There's a lot of moves you'll never use (but can still be fun to learn).
I took notes on moves I was learning as I came across them and organized them by what the move did and listed the method below it and chose one or two methods of each and practiced them (one false shuffle, one control to the top, control to the bottom, force, card reversal, etc) then I went from there.
A bit of a different perspective... We learn best when there is a reason for learning. Learning and practicing sleights for the sake of learning and practicing sleights is more difficult than learning them to perform an effect. Magic is a performance art. Learn sleights so that you can perform effects. That is why books like Royal Road and Card College teach sleights and then teach effects that use those sleights. That way, your practice has a purpose.
Ultimately, you need a couple of forces, a couple of controls, a double lift and a couple of false counts but which ones work best depends on the context of the effect you want to perform. Focus on learning a variety of effects and practicing the sleights so that you can perform them flawlessly. After a while, you will see that you've picked up most of what you need to know. I'd recommend working though Card College , it is a great foundation.