When we left our rental house, we made sure the lawns were neatly trimmed. However, while there we had enjoyed letting parts of them grow longer (albeit with mown areas too, to show that we weren’t just slacking on our duties) and it was amazing the variety of plants that grew.
One of my favourites was yellow birdsfoot trefoil, which you can clearly see in this photograph from late July. If we leave ourselves much lawn in the new place, we might try the same experiment again next summer.