My procedure would be to keep an eye out for Gasterias I didn't currently own (which at this point was almost ANY Gasteria) and begin to acquire as many as the pocketbook and the available real estate would allow. My inventory has increased to 6. The challenge I faced from the start was locating plants that were actually labeled. The ubiquitous 'Asst Succulents' was common, along with 'Gasteria spp' . Even the venerable Ruth Bancroft Garden had a few no ID's . Web sites are helpful, though often rife with conflicting information or bad photos. So my disclaimer here is maybe I have the right ID and maybe I don't. I did find an online key, which I will consult when I am feeling more scholarly.
Here is my original plant, which I have decided is Gasteria bicolor. It had a run-in with a 20 degree night a few years ago, but rebounded from the superficial damage very nicely.
This is G. bicolor liliputana (labeled !) and is one of my favorites by virtue of it's cuteness.
This mystery plant is still too small to try to ID, but I note it has a bun in the oven, and I'm hoping it's G. glomerata.
This was found at the Ruth Bancroft Garden plant sale in spring, tagless . I have tentatively ID'd as G croucheri ,but feel very uncertain-online photos are wildly variable.
This little guy was tagged, G.'Little Warty'. He is still quite small, and I expect his wartiness will become more pronounced with age .
I believe this to be G. 'Big Brother'
I snatched this one up quickly at the Ruth Bancroft sale last fall. It is Gasteria 'platinum' , the lone specimen there.