I currently use a product called MYCO+ but I’m always looking for potential other options. From what I’ve read and researched Glomus and Trichoderma strains are the most beneficial and found to populate within cactus and succulents environments. Contrary to some opinion/online advice , the bacteria can remain healthy even in a dry environment for extended periods of time. Also, if your interested in growing welwitschia mirabilis (a prized collectors plant) I have found it to be astoundingly helpful in helping them thrive (don’t ever let these plants dry out though).