For mono heads, adding an identical cabinet is the most practical solution. Stereo heads with a balance or pan can be helpful with mixed driver setups, because you can adjust relative volume/power to each cabinet to help compensate for mismatches.
My experience only - I had a Peavey 1516 cabinet back in the 90s (1-15"/2-8"). It was a nice cabinet, but I didn't see any major benefit over a regular 1-15" cabinet. I also briefly tried biamping multiple cabinets back in the 90s (10s and 18s) but saw no advantage to that, either. I've used only setups with either all 10s or all 15s since then.
In the end, find what you like and roll with it.