I know this might be a bit bold choice to some people, but hear me out. Sometimes this is exactly what you need to stand out either at the gym, festival, or just on casual lunch dates.
Patterns are so fun on any shirt to be honest, but especially on tanks. Since tanks are usually considered casual attire they do some design to make them look more elevated and patterns just do that.
This is probably the most basic choice even if the material is different like silk or something, it still gives off casual look. So it's great mostly for the gym, running, or coffee run.
Just like patterns, graphics are also a great choice. They almost add a story to your whole outfit and not to mention make it stand out when paired with something as simple as white shorts.
I love stripes because it automatically makes the shirt more formal hence they could be a very versatile choice and be paired either with shorts or pants. Either one will make a great day or night outfit.