Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5363654.
I had a classic yellow Lego castle when I was a kid and greatly enjoyed it. I designed these castle topper parts so that my kids could use them with their buckets of lego and Duplo. Duplo is essentially 2x lego so you if you want the Duplo sized versions you just print at 200%. The Duplo size is a bit more proportional to the figure size. They are designed with fillets on inside so that you don't need supports. Only the exterior corners need supports during printing and then only under the major overhang part.
There are 6 different pieces in the set, but you mostly need exterior corners and 2x4 wall pieces.
I have printed in both PLA and PETG and both have worked out just great. If you have trouble with elephant's foot there will be edge cleanup needed but even reasonably poorly tuned my machines were putting out parts that were usable without any post processing.
Enjoy.