Rhinos
The Rhino was a very common feature of Space Marine armies in 5th Edition, but it’s less required now. As discussed in the Tactical squad entry, most infantry now move and fire well without needing a transport to close with the enemy. The Rhino’s role is limited to protecting the squad inside from fire (particularly overwhelming anti-heavy infantry fire such as plasma cannons and Flamers of Tzeentch) and moving the squad quickly across the field (which it does better now that it can move 18”). One or two Rhinos may be worth taking in order to take objectives from your opponent, but they definitely have a downside. Rhinos are an easy kill, and they make it very easy for your opponent to pick up First Blood. If you take some, keep them hidden until First Blood has been scored.
Razorbacks
Razorbacks sacrifice some of the transport capacity of the Rhino in exchange for a turreted heavy weapon. While it can add some extra firepower to your army without taking up a FOC slot, a Razorback is just as easy to kill as a Rhino but attracts a lot more attention because it hurts the enemy. I tend to avoid Razorbacks now because they always seem to die almost immediately without much return.
Drop Pods
Drop Pods provide an exceptionally reliable way to Deep Strike your units and it allows Space Marines to be more aggressive than usual. Drop Pods allow safe placement of any squads inside, allowing them to shoot but not assault on the turn they arrive. In general, this benefits close-range shooty squads, and Sternguard, Command Squads, Tactical squads, and Dreadnoughts are often deployed by Drop Pods.
Due to Drop Pod Assault, half of the Drop Pods in your army (rounding up) arrive automatically on the first turn while the remainder arrives as normal. This allows you to stack your damage dealing units (Sternguard, Command squads, Dreadnoughts) in the first drop while the scoring Tactical squads arrive later once it’s (presumably) safer.