There is the room you are sitting in, the table you are working on, the noises inside or outside your home, the aroma of the coffee you have just made, the colour of the skirt you are wearing or the scaly skin on your elbows. What'e wrong with a few words about you and your surroundings? It seems banal, but it will get you started. One idea leads to another.
So, if you are describing a colour, for example, you will think of other things in that colour. A sky-blue skirt could conjure up a summer sky. That might mean an old-fashioned day at the seaside with donkeys and ice-cream or an exotic break in the Maldives. That could go on to beach entertainment or palmfuls of sun-lotion. That could turn into the secret life of the Punch and Judy man or oiled bodies scattering from a tropical storm.
Memories, dreams and plans will spring up in your head. Characters will enter your mind as you create the setting. Just don't stop thinking. It's taxing work, but it will put words on the page.
Afterwards, you may reject what you have written. So what? At least you have been working. Your work will have set new thoughts into action. You might not use those new ideas until the next writing session, but they will be there waiting in the wings.
Your mind will stagnate only if you don't use it. Not everything you produce has to be brilliant, but that doesn't mean you shouldn't produce anything. As a result of today's ramblings, you may find you have tomorrow's masterpiece.