Like Kol Korran, Waukeen is also a deity of merchants and wealth and since we already know that travel between Eberron and the forgotten realms is possible, there just might be a way to introduce some more Graz'zt content through Sharn. Sure it may be a bit of a stretch, but where in D&D cannon does it say that deities never hear about other deities from other realms? A follower of Kol Koran feeling compelled to meddle in affairs related to Waukeen might not be all that far fetched. Introducing a Sharn NPC who somehow came from the Forgotten realms, perhaps a priest of Kol Korran who used to serve as a priest to Waukeen would be an easy vehicle for such.

https://forgottenrealms.fandom.com/wiki/Waukeen

The Tethyamar Chain that introduced DDO to Graz'zt feels so incomplete, it never felt like the story Arc truly had its climax, even by Graz'zt's own words in the quest Desire In The Dark "Not quite legendary"......

Now that the Caught In The Web raid is pretty much dead, the forgotten realms need more content, and with the popularity of Sharn, you could perhaps create a new means of earning access to Eveningstar for starters.