Buckets (I have my own file but these are good ones too) https://www.thingiverse.com/thing:504388
Pole Bases https://www.thingiverse.com/thing:568388
Jump Cups ( Again, my version is a bit different) https://www.thingiverse.com/thing:617222
Furniture ( in case you want barn decor/ tack room/ office)
Ikea style shelves https://www.thingiverse.com/thing:3801792
Picnic Table https://www.thingiverse.com/thing:3406302
Dishes/ Pottery https://www.thingiverse.com/thing:1634109
Disclaimer, These are not my pictures, they are the pictures that are with the files. I did not design any of these. Some are creative commons so if you give the artist credit you can sell them but many are not. All thingiverse files will tell you if you can use them commercially. If you have access to a 3D printer give some of these a try!