Apples - self fertile
Here are a number of self fertile apple trees. A self fertile apple variety is particularly important if you can grow only one apple tree. Most apple varieties need a pollinating partnerto yield; not much use if you intend planting only one tree!
Here is a section devoted to self fertile apple trees so you can select any of these and plant them as lone trees, secure in the knowledge they will yield well.
Other sources may list other varieties as self fertile, or partly self fertile but this may not be the case. For those apples that are reliably self-fertile then stick to those listed here.