I'm pretty sure the first pic is Hygrophila polysperma 'Sunset' (a colour mutation). It's an easy, fast growing plant as long as you have enough light, it gets pinker the more light there is.
I think the second is Eusteralis sp. If it is then it likes a nutrient-rich substrate, the brighter the light the more intense the leaf colouring.
I think the third pic maybe Hygrophila stricta or maybe another Hygrophila sp.
Not too sure on the fourth pic, it looks a very small Alternanthera roseafolia.
Hope this helps.