There are dozens upon dozens of drugs used off label for anxiety. The most popular being different types of anti-depressants such as SSRI's, SNRI's, Tricyclic's,Mirtazapine, and even MAOI's, anti-convulsant drugs used for neuropathic pain such as Gabapentin and Pregabalin (brand name Lyrica), different atypical anti-psychotics such as Quetiapine and Olanzapine and even some Typicals in low doses such as Thorazine aka Largactil, Methotrimeprazine (brand name Nozinan) and Perphenazine are used off label for anxiety. Some other common drugs used off label for anxiety are the sedating anti-histamines such as Diphenhydramine, Dimenhydrinate, Promethazine, Doxylamine, Hydroxyzine, etc as well as the muscle relaxant Baclofen.
All these meds react differently to different people but basically anything that has sedation as a side effect has probably also been tried for the treatment of anxiety. Using SSRI's such as Paroxetine and SNRI's such as Venlafaxine to treat anxiety disorders was/still is the big off label use for these drugs even though there isn't a whole lot saying they work for this purpose. I have found the Tricyclics Trimipramine and Amitriptyline to work great as sleep aids and help anxiety abit as well but they certainly don't work nearly as good as say Clonazepam or any other decent benzo