Whilst I cannot say categorically that those stands are not by ATC themselves, I don’t recall seeing them on ATC’s website over numerous visits spanning the past 20 years or so. The only stands I recall seeing, though no longer shown, was a wooden tripod arrangement, quite substantial looking, with what looked like an adjustable height top section - or at least that is the image in my memory (I can’t see on their website now)
There was a thread on ATC speaker stands, including 19s:
I believe Custom Design make stands for specific ATC models.
There’s useful info on ATC’s website about stand choice and particularly ensuring acoustic axis (midpoint between the drivers on two-ways like 19s) is at ear level. That’s important as ATC speakers have narrow vertical dispersion.
The ATC importer in the USA recommends high mass stands. I’ve found high mass stands, if used on a concrete slab, work fantastically. Many who have a wood suspension floor prefer an open, lighter stand. So bear in mind the construction standard of your home when picking stands for your 19s.
Your title says ‘budget’ and the stands I am going to suggest are not that, but I used Russ Andrew’s Torlyte speaker stands with my SCM19s… and they worked really well on my carpeted solid floors (hard concrete and slate)… these stands bring the benefits of light mass open frame and wooden stands, with a resonance absorbing Torlyte platform, so in my opinion you don’t need to use some sort performance robbing viscoelastic polymer like gel pads, sorbothane or blutak.
Agree on ensuring tweeters are at ear height.
On my earlier ATCs I used the open framed SomethingSolid stands… they too worked well.
I did try various high mass filled steel stands prior over the years… and I felt each time they robbed the life out of the speaker for my tastes.