For savory meals, and baking
I typically use coconut oil as a replacement for butter, though baked goods made with coconut oil are not quite as tender as they are when made with butter. Avocado works surprisingly well for cakes and frostings, but it does impart some avocado flavor and green color -- it's best to use it with chocolate desserts to mask the color and flavor.
For savory meals, an oil of your liking should work. For baking, coconut oil is often a good substitute.
lard, ik its gross but it works
May we ask why the no butter...dairy alergy,lower fat diet, vegan, or other?
Olive oil is great in baked goods, it gives them a moist texture with a mildly olive taste which blends well with all flavors
I use a mixture of neutral unflavoured cold pressed sunflower oil and apple sauce for baked desserts. The sunflower oil is light and doesn't leave an aftertaste and the apple sauce adds extra moisture. But my recipes are all vegan and sugar free so I'm not sure how this mix would hold up in a more traditional recipe.
Pork fat is cheap at stores like whole foods and many butchers and can be used for EVERYTHING. Even just saved fat from bacon (or pork) that you eat with your eggs makes everything better plus it's cheap. I sometimes add it as a garnish to soups. It's very savory or umami
Another option is safflower oil -- I do a SIGNIFICANT amount of DF baking and that is always my "butter replacement" of choice. Just know that any liquid oil is 100% oil, while butter is up to 20% water. What that means is that whatever your butter quantity is, reduce it 20% when replacing with a liquid oil. I've had sunflower oil add a sunflowery aftertaste (just like eating sunflower seeds) so don't usually go there. Coconut works reasonably well, but can also leave a bit of a coconut flavor. Safflower is very neutral. Canola is also good if you don't have a problem using GMOs. Most olive oil is a bit heavier, so it totally depends on what you're making.
Stay organic and coconut works for us because we love the flavor it leaves behind.
Agree with SeaJambon re. flavorings of oils, and staying away from canola.
A note about canola oil: organic certification does not allow GMOs, so if you buy organic canola oil it will not be GMO.
Thank you "dinner at ten" - yes, organic will avoid any GMO concern (and since over 90% of the canola crop is GMO, really if it isn't organic it is GMO). A note that I should have added about using liquid oil to replace butter in baking -- your batter will be much more liquid. Don't worry about that, as it all works out in the end. For example, if you made chocolate chip cookies with butter, you would scoop a nice little ball of dough onto the sheet and it would spread quite a bit in baking. If you made the same recipe with oil (reduced amount as above) it will be almost a batter, and will spread very slightly during baking but nothing compared to the butter based version. In the end, the baked cookies will look remarkably the same.