These ones. As seen in the Alarm app when you Edit and Delete an alarm.

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Those are not actually custom buttons. They are a property of the delegate method:
- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath. as in:After that, all you need to do is call
[tableview setEditing:YES animated:YES];