Pollination can be done by not only bees, but butterflies, moths, flies, and even humming birds. In rare cases, even people can transfer pollen between flowers, but plants don't really rely on this.

Other than creatures, the wind can bring pollen from one flower to another, and some flowers self-pollinate. That is to transfer pollen between their own reproductive organs.

Beetles pollinate magnolia trees. Magnolias don't produce nectar but they do produce lots of pollen.

Don't forget bats! 300 species of plants depend on bats for continuing their species, including bananas, guavas, mangoes, and the agave plant, used in making tequila and sugar alternatives.