Although it's not a benzo- or SSRI, it works better for me than any of those - propranolol.
I suffer mostly from a body-anxiety, the one when you have relatively calm head (no thought stream at all) but the body goes into palpitations, shaky hands, feeling of pressure in the stomach, dizziness, wanting to run, run run! That usually happens in stressful social situations, when I become overwhelmed. I pop a pill before going out and my body stays calm. Honestly, first time I tried it - I couldn't believe something as simple solved a major problem I had throughout all my life since childhood!
Sudden sounds don't scare me that much either anymore, it's like having a fearless body
Propranolol blocks the effects of noradrenaline and adrenaline in the body. Stopping adrenaline rushes sorted everything for me. I take the lowest dose possible, so even if it gets worse, I have an option to go upwards with the dose without that much risk (blood pressure drop etc). Also, it's being tested on autistic people to see if it would improve conversation reciprocity and nonverbal communication. Initial results are positive If something that cheap and simple could solve many problems... that would just be great.