A silicone bowl that folds flat. It is the piece of kit that turns washing up from a thing you avoid into a two-minute job, and the reason is arithmetic rather than comfort.
Washing up under a running tap uses an enormous amount of water. Washing up in a bowl uses what the bowl holds. Away from mains, where every litre was carried and possibly treated, that is the difference between doing the washing up properly and leaving it until the pan has a crust on it.
Two bowls is the better system if you have room: one to wash in, one to rinse in. A single bowl means rinsing in water that is already dirty, which is how detergent ends up in the next meal.
The collapsible ones nest into almost nothing and double as a basin for soaking pulses, a salad spinner substitute, and somewhere to put the washing up while the pan is still on the stove.
Check the rim is rigid. A fully floppy bowl with four litres of hot water in it is hard to carry to wherever you are pouring it away, which is the moment this matters.