Once you get a roof rack you’re able to mount nearly any equipment you’d need for an outdoor adventure. Most racks hold around 100 lbs. So that could mean bikes, kayaks, or snowboard.
Another common use is to add some additional space to your vehicle for a camping trip, or any trip! That’s achieved by adding a roof box. We even wrote a guide for roof boxes that would work with your Rav4 here.
If you don’t want to commit to a roof box but still think you’d need extra cargo space, consider getting a cargo bag! They’re made of fabric and most are waterproof. A much more affordable alternative to a hard shell box.