Weighted step ups
Deadlifts, both regular and stiff legged (great for the hamstrings, glutes and lower back, aka posterior chain)
Squats for sure, you already mentioned them. But they call them the king of exercises for a reason.
I'm a big fan of compound lifts for general fitness, isolation moves like leg extensions/curls and to a lesser extent leg press are for bodybuilders looking for mass rather than strength.
Just my opinion