There are a number of specialized items that are used in planar adventures, whether for transportation, defense, survival, or advanced weapons that prove effective versus extraplanar creatures of all kinds. These items are highly magical and often complex, and many were developed outside the Material Plane. Some are more affordable than others, and more common, but still available in the Multiverse.
Armaments are required for travel in a large amount of the Multiverse. Though ranged weapons are more common, they are not always as effective, as certain defenses have been developed to negate such attacks. Many ranged weapons are limited by a capacity of projectiles, or durability, as the magic is heavily destructive and focused.
Melee weapons are often lightweight and magical in some variety. Most are indistinguishable from their mundane counterparts, and appear made with exceptional and exotic craftsmanship. Some weapons are made to function more effectively for a certain race, or be easier to wield.
Much of the extraplanar apparel is suited towards astral travel or defense. There are many options that allow for less rugged creatures to survive in foreign planes' climate and atmosphere. Interplanar travel, trade, and tourism is commonplace, and these items are not extremely rare, rather available at the right shop.