Human hair keeps most bigger pests away. For the smaller pests, grow some beneficials nearby: chamomile, buckwheat, marigolds.

Cats are tougher. Half filled bottle of water left out in the yard is supposed to startle them (light reflects in clear bottle frazzling them). They hate snakes so small pieces of hose might help. Plant Rue. "rue the day". Or some catnip at the other end of the garden.