When designing iRules for selecting a pool for load balancing, the most relevant events would involve intercepting and processing the initial client request, handling the HTTP request itself, and selecting the server from the pool. 'CLIENT_ACCEPTED' is important as it triggers when a client establishes a connection, giving an opportunity to apply load balancing rules. 'HTTP_REQUEST' is essential as it processes the incoming HTTP request, which is crucial in determining which pool or server to select. 'SERVER_SELECTED' is relevant because it deals with the routing and selection of the appropriate server from the pool based on load balancing logic.