Question

1. Teamwork is more important than anything else.

2. Teamwork is more important than any other thing.

3. Teamwork is more important than all the other things.

4. Nothing is more important than teamwork.

5. Nothing is so/as important as teamwork.

6. Nothing else is more important than teamwork.

7. Teamwork is the most important thing (of all).

(Are all the same expressions? Do you have other similar expressions. Do I have to use 'of all' in #7?)

Answer 1

#2 is awkward.... Other than that, you may use all the other sentences.
On 5 "as" is preferable to "so".
No, you do not need "of all" on 7.