It's difficult to know which 4 to recommend... but here are my sugggestions:
1. Core Logic - Logic 101. Great tutorial. All the basics and more included. Essential viewing! Takes you through recording and producing a song from start to finish:
2. Logic 104 - Flex Time Editing. Great if you want to be able to record audio (e.g. vocals) and they are not in time. You can use Flex to correct the timing:
3. Logic 102 - Exploring the EXS24. As you use Jam packs, I imagine you also use the EXS24 sampler. This tutorial will help you understand how to use and create your own sampler instruments.
4. If you need to adapt Logic's grid to match the changing tempo of your recorded performance, then you need to know about Beat Mapping. So much more included in this tutorial too!
But, there's a whole range of Mixing, Mastering tutorials and of course, if you want to learn about creating your own drum patterns then Ultrabeat Unleashed should be explored, if you need to understand synthesis, ES2 and Sculpture are essential viewing...
...So hard to recommend only 4 tutorials!
Hope this help