Yup, “probably” is the key here. All three have both name brand versions and generic versions – the makers of the generic versions usually keep that color scheme, for simplicity, but I’ve occasionally seen saccharin in yellow packets, for example.
And, stevia is usually in a green packet.
Saccharin is the oldest of the lot, having been discovered in the 19th Century. I find it has a fairly horrible taste, but back in the day, it was one of the few non-caloric sweetener options. In the 1970s, research suggested that it could cause cancer, and the FDA mandated that saccharin carry a health warning. Later research indicated that, at the levels at which people actually use it, it’s probably safe, and the warning was removed from the packaging. The cancer concerns in the 1970s, linked with the advent of aspartame, cost saccharin a lot of its former market share, but it still has its adherents – I suspect that a lot of people who still use it are older, and who had started using it when the other options weren’t available.
Aspartame was accidentally discovered as a sweetener – it was originally discovered during development of an anti-ulcer drug, during which a researcher discovered that it had a sweet taste. It breaks down under high heat, so one place it’s not used is in cooking and baking, but it works well in beverages.
Sucralose is newer still, and was approved for use in the US in 1998. Unlike aspartame, it works well for baking and cooking.
Unlike the “big three” above, stevia is naturally-derived – it comes from the leaves of a South American plant, and had been known as a sweetener for centuries. It’s only been in the past few decades that it’d started to be used as such in the US, and has only had widespread use over the past decade or so, when the FDA finally approved its uses as a sweetener.