Here is what Mike Mentzer called in the early 2000’s his most productive routine, a 2 way split, typically training one on and one off. It’s from Ironman but I am crediting and cutting and pasting in case the link needs to be eliminated:
Workout 1 (Monday)
Legs
Superset
Leg extensions 1 x 6-8
Leg presses 1 x 6-8
Squats 1 x 6-8
Leg curls 2 x 6-8
Calf raises 2 x 6-8
Toe presses 1 x 6-8
Chest
Superset
Dumbbell flyes or pec deck 1-2 x 6-8
Incline presses 1-2 x 6-8
Dips 2 x 6-8
Triceps
Superset
Pushdowns 1 x 6-8
Dips 1 x 6-8
Lying triceps extensions 2 x 6-8
Workout 2 (Wednesday)
Back
Superset
Nautilus pullovers 2 x 6-8
Close-grip pulldowns 2 x 6-8
Bent-over barbell rows 2 x 6-8
Traps
Superset
Universal machine shrugs 2 x 6-8
Upright rows 2 x 6-8
Shoulders
Superset
Nautilus laterals 2 x 6-8
Nautilus presses 2 x 6-8
Rear-delt rows 2 x 6-8
Biceps
Standing barbell curls 1 x 6-8
Concentration curls 2 x 6-8
IT comes out to 18 work sets a day or 63 per week if training one on one off, and he lists 7 bodyparts, which would be about 9 work sets a week (though hamstrings and calves are clumped with “legs”. Muscles are getting 5-10 work sets a week on average, 8-10 for larger groups, 5-7 for smaller.
https://www.ironmanmagazine.com/heavy-duty-mike-mentzers-most-productive-routine/