Squats. Every top athlete does some variation of these just about every block/phase/stage of their athletic careers. With there literally being dozens and dozens of different variations of them as well. Now obviously not everyone is going to be able to do a back squat or front squat with no prior knowledge of how to do them. There should be some sort of track that you would follow such as
1. Body weight box squats
2. Lower body weight box squats
3. Box squats with a bar
4. Goblet box squats
5. Goblet squats
6. Front squats
7. Back squats to parallel
8. Deep back squats
9. Overhead squats
10. Pistol squats
Some kind of order like this where you are working on mobility before attempting the more technical lifts is optimal.
Now it’s not to say from the list you have to exactly go from 1-2-3etc., but you can progress like 1-4-6-8 or something like that. Not everyone progresses super fast and some do.
Let’s get to the main point of this. Other than clean and jerks and snatches, in my opinion, there is no greater lift for building athletic performance, strength, or health in general than the squat. You may hear things like “squats are bad for your knees/back” or whatever, but that couldn’t be further from the truth. In fact squats help actually build strength around these areas, and around everywhere in the body. Going from your quads, hamstrings, glutes, lower back, upper back, and just your core all around there is no greater lift.