I guess there is a certain grouping here that is missing, something like:

Bucket A: The Implementation

• 1. Hardware: A physical appliance.
• 2. Software: A program (Nginx/HAProxy).
• 3. Cloud: A managed service (AWS/Azure).

Bucket B: The Scope

• 4. DNS Load Balancing: Global, before connection.
• 5. GSLB: Global, smart DNS.
• 6. Hybrid: Uses both DNS and Internal balancers.

Bucket C: The Logic (How does it route?)

• 7. Layer 4: Routes based on IP + Port (Fast, Dumb).
• 8. Layer 7: Routes based on Content/URL (Slower, Smart).