-D28: Dana 28 model based axle. The Bronco II had a small front axle and it was pretty weak. Fine until you got above 33" tires (like I had), then the little u joints would just snap under high load. D35 in the Explorer had larger axle shafts, and a larger pumpkin which also allowed for lower gearing to run larger tires, 35s would be fine. 35's on that small of a vehicle are pretty good.
-7.5: rear axle, not a Dana model, but Ford. Ford models are named by the ring gear size. 7.5 could handle all the power of a Bronco II, but the 8.8" also brought other benefits like rear disc brakes. And since it was used on the Mustang and F150, lots of available parts.
-2.9: Bronco II had a 2.9 liter V6 that made 140 horsepower. Mediocre at best. The 4.0 was basically an improved 2.9 that made it stronger and more reliable.
-TTB: Twin Traction Beam. Ford's way to try and get the advantages of an independent suspension, and the advantages of a solid axle. Great compromise that improved street handling, but still allowed for a massive amount of suspension travel. Still a compromise, but better (in my opinion) than any other suspension for that purpose. Everything since then has been road focused only.
-SAS: Solid Axle Swap. If you are going to be serious about low speed off roading, you need a solid axle (like the Wrangler still has to this day). Pretty common even to this day replacing their independent front suspension for a solid axle for better off road capabilities.
-D44: An even larger axle than the D28 or D35. Stock Wrangler has a D35 in the front, D44 in the back. Rubicon package gets dual D44 axles (what I have). Those are good up until around 37" tires, then you need a D60, unless it is just for looks (like 90% of Jeeps).
-V8 swap: self explanatory
I don't like wrenching much any more. Partially from making it my career, partially because I have gotten so big into athletics so I am too busy, partially because I don't have the resources. But I still prefer to do as much of my own work as possible.