Hi

   They are leggy but can still grow strong.   How far above the plants are your lights?  Are the lights natural spectrum?

   Ideally,  lights should be 1 or 2 inches, up to 4 inches above  growing plants.  If using fluorescent  bulbs, you can use 1 bulb cool spectrum and 1 warm spectrum or 2 shop lights.  Hang light fixture on chains so you can adjust height as the plants grow.  

    With them being leggy, close lighting is essential.  One source I read said to have a gentle breeze from an oscillating fan for a few hours a day to toughen the plants.  

   Tomatoes, you can plant them deeper in the garden when you transplant them.  I included a basic tomato care article for you also.

    Sunflowers are probably leggy due to light also.  Starting plants in temperature of around 70 degrees helps also.

  If you have further questions or concerns, please ask!  

https://extension.umn.edu/planting-and-growing-guides/starting-seeds-indoors

https://extension.umd.edu/hgic/topics/tomatoes

https://extension.umn.edu/flowers/sunflowers

https://extension.umd.edu/hgic/topics/pvc-light-stand

https://www.johnson.k-state.edu/lawn-garden/agent-articles/vegetables/lighting_options_for_Seeds.html