Here's a list of material from the Dungeon Masters Guild that can be used to supplement the Light of Xaryxis campaign. Feel free to post in the comments if I've omitted something. I did not include material intended specifically for VTT play.
Stars Over Stormwreck
This scenario acts as a bridge between Dragons of Stormwreck Isle, the scenario from the D&D Starter Set, and the Light of Xaryxis campaign. Although I used Spelljammer Academy to launch my campaign, I'm thinking of using that pairing to launch a future campaign that would then lead into Graveyard of the Gods.
https://www.dmsguild.com/product/412377/Stars-Over-Stormwreck
Spelljammer Academy Expanded
I've previously posted about this supplement, which adds more content for use during the PCs' time at Spelljammer Academy. If I had had more time for running my campaign this year, I definitely would have used it.
https://www.dmsguild.com/product/408703/Spelljammer-Academy-Expanded
Orc Chief's Throne
This scenario is intended as a bridge between Spelljammer Academy and Light of Xaryxis, one that gives the PCs a chance to acquire their own ship. It looks like it could be pretty combat-intensive, and ultimately I decided not to use it, but I was tempted.
https://www.dmsguild.com/product/410026/Orc-Chiefs-Throne--Spelljammer
Saving Commodore Krux
This is the first of three scenarios that supplement specific chapters in Light of Xaryxis. This one expands on the events of Chapter 4, adding more activity while the PCs are on the Rock of Bral. The preview looked solid, but I ended up not adding it.
https://www.dmsguild.com/product/415345/Saving-Commodore-Krux-a-Spelljammer-Adventure
Of Mercanes and Megapedes
This scenario expands on the PCs' interactions with Vocath the Mercane and the factions of Doomspace during Chapter 8; once again, I chose not to use it due to time constraints.
https://www.dmsguild.com/product/416190/Of-Mercanes-and-Megapedes-a-Spelljammer-Adventure
Mind Flayer Over Matter
In a previous post I mentioned that I added this scenario to the campaign. It worked well for adding a few encounters between Chapters 9 and 10 during the lead-up to the campaign finale, buying some time for a player who needed to miss a couple of sessions and allowing everyone to advance their characters to level 9 before the big final fight. I did not do a good job of preparing to run it, however.
https://www.dmsguild.com/product/418858/Mind-Flayer-Over-Matter-a-Spelljammer-Adventure