MisterEric
Nope, with the demise of Bluette, that only leaves Mrs. Stewart's as the only liquid bluing on the market.
IIRC, you still can find bluing powder and or cubes (dolly blue), in the UK, EU and some Commonwealth countries, but as on these shores you may have to hunt to find it.
Bluette and Mrs. Stewart's are two different types of bluing.
Bluette is a Prussian blue that is (ferric ferrocyanide) and water. More exactly it is a colloidal suspension since the ferric ferrocyanide does not mix with water.
Modern Mrs. Stewart's bluing is also a Prussian Blue (Ferric Hexacyanoferrate), but not too sure about vintage versions. Have a an older glass bottle of the stuff and it looks and behaves like ink. Indeed am told this particular form of liquid bluing was used also for writing purposes.
While excess or stains from Bluette are some what easy to remove (same goes for dolly bag and bluing cubes), Mrs. Stewart's is another matter. At least the vintage version in my stash can and has stained counter-tops, dish-cloths, and laundry. Nothing like haning white sheets on the line to find little blue dots or stains. When this happens, one is supposed to soak the item in ammonia and water, and often you are totally out of luck.
OTHO vintage Mrs. Stewarts does give a more lasting blue "tint" than other bluings I've used.