MC and Visa by Netspend (netspend.com) are still useable on ALL casino places who take credit cards. They are a prepay, costs $1 per transaction, and I’ve used them for years.
They have sworn from the beginning of all this that they will never presume to tell me what I can or cannot do with my own money.
You can load them via other credit cards (that allow it), through PayPal, at a huge number of physical locations and even by bank – although these days I’d say hooking my bank account up to anything at all online isn’t too wise.