My personal picks:
Chest: undecided between low-incline barbell bench and high-to-low cable press. You basically combine the movements from a decline press and flyes on a cable crossover machine.
Lateral delt: I have always been able to hit both my front and side delts insanely well and equally with barbell overhead press only. High-rep lateral raises would be my pick if I had to choose an isolation movement.
Front delt: Same as above. I’ve found Scooby’s way of doing bent-arm db front raises to be the best in my case.
Rear-delt: Band pullapart. End of story.
Quads: I haven’t done any isolation work for quads in ages. Due to structural issues of my left knee, there’s only a handful of extension machines that don’t put any strain on them and sadly the only one in my town is in a gym that sucks otherwise.
Hamstrings: Unilateral leg curls are holy.
Biceps: If you have bands, put a light band on a very heavy dumbbell and position it in front of a scott curl bench so that it doesn’t give you much resistance when starting the movement. Once I got this working, I have utilized bands in every single bicep workout since. If bands are not an option, spider curls are awesome. These can be done with an incline bench without bracing your triceps against it or if your scott bench has a straight pad on the opposite side, brace your triceps against it to make the movement even more effective.
Triceps: Cable pressdown with a wide grip. I got these from a video where Ed Coan explained he liked training triceps with the same grip he uses while benching. I tried them and found that they hit my triceps like no other movement.
Calves: Standing calf raises if I have to name something. I haven’t trained mine in 4 years.
Abs: Ab wheel and standing cable crunches are awesome.