BioWare seems to have no plans on releasing DLCs for Dragon Age: The Veilguard. However, creative director John Epler has given insight into the probability of releasing a Dragon Age remastered collection.
BioWare Doesn't Have Current Plans for Dragon Age: The Veilguard DLCCreative Director Says “Never Say Never” to Dragon Age Remastered Collection Though
While further details on BioWare's plans for a Veilguard DLC weren't shared, Epler did give comments on what the devs think about releasing a remastered collection of older Dragon Age games, similar to what they have done with the Mass Effect Legendary Edition which modernized Mass Effect, Mass Effect 2, and Mass Effect 3 for today's consoles.
Epler noted that while he would love to see a Dragon Age collection be released, remastering the first three Dragon Age games would be challenging as they originally used EA's proprietary game engines. Epler explained, "It’s something that’s not going to be as easy as Mass Effect, but we do love the original games. Never say never, I guess that’s what it comes down to."