Some of the more popular cages:
HQ cages are sturdy and are built to last.
These three are from EN Brisbane from EN
One I currently have and love so far. Madagascar
I personally had this cage before, and loved it as well, for the most part. A bit more room than the Brisbane. Congo
I haven't had this exact cage, but one very similar from a different website. I'll post those as well.
Sucoast Gliders, sadly temporarily closed due to hurricane damage. HQ Sturdy
This cage is like the Brisbane, not sure if exact, but at least similar. HQ Large Sturdy
This is the exact cage I had previous to the Brisbane. I really liked this cage. I chose this over the Congo because I figured it would be cheaper with the flat shipping rate, though it was priced slightly higher in price. This one has six extra sliding, feeding doors on the front, I'd prefer not to have, the Congo I believe doesn't have these.
Another very popular cage type are Critter Nation and All Living Things. Critter Nation
This is the website for CNC cages. It's popular due to large size and the two large doors, also, some prefer the horizontal bars. The downside is the lack of sliding floor/drop pan, but some have managed a trick to fix that issue. You may find this cage on other websites, maybe Amazon. All Living Things Multi-Level
This cage is equivalent to CN cage I believe, sold by PetSmart.