Stellaris: Console Edition released absent the 3 years of DLC the PC edition had already experienced. Following that roadmap the first DLC for the console is the same as what was for PC, Planetoids, released earlier this week. This is the first step in the planned roadmap that will also include the Leviathans DLC on April 16th, multiplayer introduced May 21st, and the Utopia expansion in Summer 2019.
Planetoids is paid DLC and comes in at $8. I really enjoyed the base game, giving it an 8 of 10 in my review; but on the face of it, I'm still not sure why that game wasn't released with DLC parity with the PC... While there is a Digital Deluxe edition that includes all DLC as well as a Deluxe Upgrade Pack that adds the same to a base game purchase, the reviews for Planetoids from the PC edition are pretty easy to look up. If you need someone to save the googling for you: it's pretty much all cosmetic here. So if you really need those better portraits and ship styles, then by all means you spend your money with whatever makes you happy. But for DLC that is going to have a real gameplay impact, that's not really coming until April 16th.