M.Blokh's book "Combinational Motifs" or "Combinative Motifs" is a really nice book, and suitable for anyone between 1000 to 2300. The layout is very clean and logical, and the puzzles are organized in a logical way that will train your brain instead of overwhelming it, but it's important to remember that in most published puzzle books, many problems are often used in different books, so you may have seen some of the solutions before, if you've read any other good tactics puzzle books.
John Nunn's puzzle book is more geared towards advanced players (1600+) who want problems that are fresh and not of a generic "white to move and do a double attack" nature, so I would only recommend such a book after first finishing a good standard one.
Please don't do online algorithm generated puzzles as an attempt to get better...you'll go cross eyed (and quite insane, too).
I'm wondering if there is any general consensus on the very best collection of tactics training exercises, for beginners to 2000. Is it a book? An online course? What I'm searching for is something you can recommend to a beginner, and say, "This has what you need to learn tactics."
What I'm looking for is an organized collection, not random puzzles. Hand-chosen material, not just a collection or data base of positions from games generated by a computer and sorted by theme. Something that a GM or IM or maybe a NM put together, not to sell books or courses, not to entertain, but to logically present all the patterns a beginner needs to know to get to be rated 2000, and ready to learn position play. Perhaps no single work like this exists, but several works, one for beginners, one for more experienced beginners, then one for intermediate players, then advanced, but non-master players. Or maybe nothing exists at all that is definitive.
Polgar's book "Chess" comes to mind, but I'm not convinced that it is methodical. I suspect it is just a lot of random examples. Random positions sorted by theme anyone can get on Chess.com.
What I'm looking for does not have to have verbal explanations. Just diagrams and solutions are fine, but only if carefully chosen to be both thematic, instructive, and practical, the sort that players 1000 -2000 will encounter repeatedly in their own games.
What do you suggest?