Let the couple's taste guide your choices. The first Rakhan Bandhan for newlyweds is naturally a good opportunity for some elaborate picks for the couple: think Kundan stonework, pearl clusters, or zari threadwork in bridal red or gold. If you're shopping for a couple with a taste for things more understated, minimalist evil eye pairs, sets in oxidised silver-tone, or muted pastels in resin may be a good fit.
For the couple that likes a little luxe, consider the other offerings that spark a little joy. For a Rakhi that will be worn for a few days, consider a thread-and-bead combo. Kundan and American diamond sets are great for maximum sparkle. Just keep in mind that your Bhabhi will be suspending the Lumba from a bangle, so it's more important that it has a good clasp than a wrist rakhi.
If you won't be able to share the moment in person, consider Rakhi combos that include roli, chawal, and mishri, as they will let the couple perform the rituals. Other offerings with almonds, cashews, or Ferrero Rocher will add some extra treats to the parcel for the couple.
Keep in mind the travel. If the Rakhi is going from India to the USA, Canada, or Australia, steer clear of the more delicate floral or feather embellishments, as they won't make it through the travel as well as metal-based or stone-set designs. Every product page has a description of the material and what it comes with, so you can compare before making your choice.