OneMail downloads all your emails for blazing fast offline searches. A great app for email addicts, makes it snappier to manage email on the go.Apart from that, full text search in a fraction of the time the built in Mail app takes.
The app works well with all POP/IMAP accounts.
Google had recently Open sourced reMail. I feel this is just the replica of that with minor upgrades. But what’s still worth the price is the support that they offer.
Price: $0.99 (iTunes)