Honestly, it is hard to find a good “free” VCC that really works. Most free/random VCC generators get declined quickly, especially for free trials or platforms with strict payment checks.
If you really need a reliable VCC, you may need to spend a small amount to test. It also depends on your use case.
Some VCC providers support many different categories, but their cards may be easier to decline. Some providers focus on specific verticals. For example, Adpos and Brocard are more focused on advertising payments. If you use them for ad platforms, the experience is usually much smoother because they are built for that scenario.
So I would first check what platform you want to pay for, then choose the VCC provider based on that.