To create all possible combinations as per the structure you've described, we start by forming all two-digit pairs from the digits $1, 2, 3, 4, 5, 6$. Each combination will then use a remaining unused single-digit as the final digit in the format $\text{two-digit number}, \text{single-digit number}$.

Here's a structured way to proceed:

1. Generate two-digit pairs: We create every possible unique two-digit combination from the digits $1$ through $6$ (e.g., $12$, $13$, $14$, etc.), ensuring no digits are repeated within each two-digit pair.

2. Assign an unused single-digit: For each two-digit pair, we select a single digit from the remaining numbers (excluding the digits used in the pair) to complete the combination.

3. List all possibilities: We compile every combination in the form $\text{two-digit number}, \text{remaining digit}$, ensuring each digit is used only once in each combination.

Let’s calculate the combinations according to these rules.I've created the combinations according to your specified structure. There are a total of 120 unique combinations. Here are the first few examples:

1. $12,3$
2. $12,4$
3. $12,5$
4. $12,6$
5. $13,2$
6. $13,4$
7. $13,5$
8. $13,6$
9. $14,2$
10. $14,3$

Would you like the complete list or have any questions on the methodology?

Here are some follow-up questions you might find useful:

1. Would you like to explore combinations with repeated digits in the two-digit pair?
2. Do you need combinations that involve a different set of digits or a different number structure?
3. Would you like to see the combinations visualized in any particular way?
4. Should we sort the results in a specific order, such as numerically or by unique two-digit pairs?
5. Are there any additional constraints you'd like to add to these combinations?

Tip: Using permutations for generating combinations can be flexible; changing parameters (e.g., digit counts) will modify the pattern easily.