https://en.wikipedia.org/wiki/Valonia_ventricosa
https://en.wikipedia.org/wiki/Foraminifera
Even some bacteria can grow to visible size:
https://en.wikipedia.org/wiki/Thiomargarita_magnifica
There are some other examples here:
https://en.wikipedia.org/wiki/Largest_organisms
http://cnet.com/home/kitchen-and-household/appliance-science... verifies this.
Which, ironically, are both only haploid.
https://en.wikipedia.org/wiki/Valonia_ventricosa
https://en.wikipedia.org/wiki/Foraminifera
Even some bacteria can grow to visible size:
https://en.wikipedia.org/wiki/Thiomargarita_magnifica
There are some other examples here:
https://en.wikipedia.org/wiki/Largest_organisms