Yeah, we're certainly not restricted to just the syllabus. As I said, I'm working through the advanced bronze syllabus, but I've done most of the social bronze steps at one time or another, and also several of the dancesport steps.
Each syllabus (at least the advanced and dancesport ones. Social syllabus is similar, but maybe slightly different), are also broken up into sections.
Beginner = Patterns 1 and 2
Intermediate = patterns 3-5 (or 1-5, depending on how you want to look at it)
Advanced = patterns 6-8 (1-8)
Full bronze = patterns 9-10 (1-10).
These divisions are used during competitions to help keep studnets from having to compete against students much better, or worse, than them. We also use them at our studio to split up the groups. Because pros use the same splits as a rough idea of how deeply they'll go into technique with a student (though if you're willing to suffer, they'll teach you all the technique you can fit in your head

), these splits are useful for group lessons. Even if a particular pro has never taught some of the students in that group, they know that an advanced bronze student will have their knowledge of rise and fall, or cuban motion, or proper promenade frame, etc, at a certian level. Helps their be a more equal footing for teaching, not just competing. That makes it easier on both the students and the teachers.
Advanced Bronze American syllabus currently contains:
Waltz
Tango
Foxtrot
Viennese Waltz
Paso Doble (Yes, american paso

)
Rumba
Chacha
Mambo
ECS
WCS
Samba
Merengue
Hustle (I think, I don't dance it)
Salsa (this is most recent addition, so not all of the studios have the paperwork and videos for it yet).
Argentine Tango
Think that's all of them off top of my head. I only dance 7 of them regularly and as part of my "program.". So compete and only have to test out of those as I test each level of bronze, though I will at least dabble in the others. Ah, which is another point. The testing. As you go from each of those levels mentioned before, you "test out" of the previous level. A pro am student will do each dance with their pro, and then one or two steps (believe I did just step 2 for beginner test, and steps 3 and 5 for intermediate test) by themselves. They are given a proficiency style score, 1-100, and also detailed feedback. When we do them at studio, generally onely have one or two students at a time testing, so tester will go over the results and work with the student on some of the things they noticed need to be fixed.