The cucumbers are the first ones to grow. I have seen signs from some tomatoes too, but not as strong as these two. :) 
And I found a bag of strawberry seeds that might be too old, but I'll try them anyway. Last date to be sold was 2019, so hopefully they still have some 'juice' in them. They like to grow in the dark, so I need to make room in a cabinet for them... and not forget about them! :D

Edit: I've seen two more cucumbers and six of the tomato plants showing signs of growth. The other cucumbers are as big as these two! :)