Cross pollination should be taken under consideration for other fruits as well, although there are some that are self-fertile.
Pears: European types will do better with a pollinator, while Asian types are considered self-fertile. Seckel is considered partially self-fertile
Cherries: The Blackheart Cherry is considered by some to be partially self-fertile, but for best results, plant a pollinator. Tart cherry varieties can cross pollinate the Blackheart if bloom is concurrent, other sweet cherries can also provide cross-pollination.