Everyone's favorite gym equipment?

hey yall; I started going to the gym about 3 times a week mid Jan, for varying times depending what works each day (30mins to 4hr)

I normally do at least 30mins on treadmill with a good incline, then work on areas that I'd like to shape down (Abdomen & thighs);

Given all of that; Along with tracking calories with MyFitnessPal and diet changes, I've gained 1-2 lbs (A nurse mentioned it could be muscle gain, whicu is plausible)

anyways- Wanted to ask for those of yall who go to the gym, what equipment/machies do you like best, and what areas do they target? (Side-tangent: I'm not sure how to figure out what amount of weight to put on each machine so if anyone had any idea there too that'd be great <3)