Windmills, Sacrifices(Clearance and Exchange), Desperado, Decoy, Deflection. Those are some common ones that are useful to know.
Tactics Levels

Windmills, Sacrifices(Clearance and Exchange), Desperado, Decoy, Deflection. Those are some common ones that are useful to know.
Overload. Sealing and Sweeping.

Thank you. I am writing those down to look into for my next set of motives
I also managed to find this group: Advanced Pawn, Attraction, Double-Check Pawn Tactics, Trapped Piece, Weak Back-rank, Zwischenzug. I hope to figure out which 6 would be most useful out of the options posted in this thread.
* It kind of looks like there is Basic, then everything else.

Here's a Decoying and Diverting combination (from one of my games):
And an overload combination, also from one of my games (but in the actual game, it was Black's move, not White's).
Attraction, Decoy, and Deflection +1. They are similar in the that they all involve forcing a piece to move, so worth learning together. @blueemu's was a terrific example.

@blueemu posted great examples! Hopefully that gives you a sense of "advanced tactics".
Am I right then that we don't really have intermediate tactics? Just Basic and advanced?
Agreed. I've never come across that classification. There are tactics and combinations, so maybe that is what you are thinking of. A combination involves a sacrifice and a forced sequence where you expect to recover the sacrificed material plus an advantage. But if you want to think of any sequence of two or more tactics as advanced, that's fine.

Sealing and sweeping is a very rare tactical motif, which involves luring an opponent's Pawn to a particular square in order to prevent him from using that square for a piece instead, and then bypassing the Pawn (leaving it marooned on the square) and attacking along those lines that were opened by the maneuver.
An example will make it clearer:

What would you think of focusing on end game puzzles? Would you hold off since you would need to get to endgame situations before they will be meaningful or work on them as well?

It's certainly worth knowing the principles of endgame play, especially King-and-Pawn endgames and King-Rook-and-Pawn endgames. It's hard to make sensible decisions in the middle game if you don't know which endgames are won and which are drawn.

Guard Destruction is another useful tactic: a temporary sacrifice to knock the props out from under an important enemy piece.

It's certainly worth knowing the principles of endgame play, especially King-and-Pawn endgames and King-Rook-and-Pawn endgames. It's hard to make sensible decisions in the middle game if you don't know which endgames are won and which are drawn.
I am actually learning one endgame position every day and those are the two I started with.
For endgames I really recommend Chessable (google it). There spaced recognition technique and daily reviews are a great way to learn the techniques. They have a number of free endgame courses. Basic Endgames is good. I use Chessable in conjunction with Silman's book. The drills and lessons on here are also useful.
I am currently doing puzzles to improve my tactics. I take 15-30 minutes and do just one theme. After that, I do a puzzle rush survival and try to get to at least 20.
The Basic themes I am doing now are: Mate in 1, Mate in 2, Forks, Skewers, Discovered Attacks, Pins. (Those were mentioned in various places as the themes a Noob needs to work on)
My question is, what would be considered Intermediate and Advanced tactics?
If anyone has a link where this was already discussed, then I would be glad to follow and read that.
Thanks in advance for any replies.