Exactly what you get depends on the package. Here’s the full set.
The online course: Each part is split into units and each unit into small topics. That sounds minor but it helps. If you only have half an hour after work you can finish one topic and close the laptop. It works on a phone too.
The question bank: This is why most people buy Gleim. There are thousands of practice questions across all three parts. You can sort them by topic and build your own quizzes. When you get one wrong the explanation tells you why the right answer is right and why the others aren’t. Honestly that second bit teaches more than the textbook.
The exam simulator: It copies the layout and timing of the real SEE. A few full mock exams will show you whether you actually manage 3.5 hours or run out of time on question 80.
Outlines and books: The outlines are short summaries of each topic with no extra theory. Some packages add printed books and plenty of people like to scribble in a real book.
Video lectures: Higher packages include an instructor walking through each topic. Good if reading tax rules puts you to sleep.
Flashcards and audio review: These are handy for tax limits and deadlines and thresholds. The audio is something you play in the car or on a walk.
A personal counselor: You get someone to help build a study plan and answer questions. If you stall halfway through a course this can be the difference between finishing and quitting.