The 993 "compound" kanji components
All the 3,530 most important kanji can be broken down into just 270 "atomic" components. But sometimes, these atomic components appear again and again in the same combinations. These combinations are also considered kanji components in the Kanjisense system, and given names. As with the atomic components, learning to recognize these "compound" components will help you to learn new kanji much more easily.
The problem is that, as with the characters themselves, there are more than a thousand of these compound components. Therefore, they don't lend themselves well to rote memorization. But the good news is that most of the compound kanji components double as standalone characters. So there is not really any need to learn them separately from the characters themselves. They are listed here for your reference.
666 compound components doubling as standalone characters
As for the remaining compound components in the 3,530 most important kanji, which do not appear as standalone characters in modern Japanese, there are just 327 of them listed in Kanjisense. Many of these components were indeed once used as characters long ago, but have since fallen out of use. Others are simply graphic elements that appear in multiple characters at once for historical reasons.
In any case, I still don't recommend trying to memorize these compounds by rote. Rather, it would probably be easiest to focus on these components as you come across them "in the wild". If you 1) learn one character containing one of these components, and 2) have that component pointed out to you as such, that should be enough to help you recognize the component in other characters.