Based on my research while other weapons are sentient, Xal'Atath appears to be the only one that references the old gods.
However there are some quotes from within the Emerald Nightmare Raid that are relevant
Quotes by Xal'Atath
The only clear cut references were those in the question, but there some others that based on my research appear to be related
While in Azuna
The Legion burrows deep here. If they burrow deeper, they may not like what they find.
At the end of Emerald Nightmare
The God of the Deep writhes in his prison, breaking free ever so slowly. You should hurry and defeat the fallen titan... there are greater battles yet to fight.
While in Val'sharah
Here you will see why the Legion's invasion is ultimately futile. All
can be corrupted, dreams and demons alike.
Potentially hinting that maybe the Legion isn't our most pressing enemy.
While in Stormheim
Do not be impressed by tall icons of the titans which stand here. The towers >! of sacrifice in Ny'alotha dwarf these pathetic temples
Mention of the sleeping city, more on this below.
While in Suramar
This city of the elves pales in comparison to the sleeping city... (Near Suramar City)
Another mention of the sleeping city
Quotes by Il'gynoth
Most of these are not clear cut, don't really stand on their own as a reference, but with further investigation appear to be relevant.
Randomly during encounter
Five keys to open our way. Five torches to light our path.
This is talking about the Pillars of Creation and potentially how they would be used to open the prison
At the hour of her third death, she will usher in our coming.
This appears to refer to Sylvanas and that she may have something to do with opening the prison
N’Zoth… I journey… to Ny’alotha…
Direct reference to the 'last' old god and to the sleeping city that may be the void version of the Twisting Nether
The lord of ravens will turn the key.
Referring to someone who may be responsible for opening the prison.
In my research I came across this brilliant post that speculates on a lot of the hidden meaning behind these quotes.
Conclusion: They're coming.