test methodologies Questions

There are many tools available in the market for automation testing.But which is the best tool to start with who does not have experience in Automation testing but has worked on manual testing.

As I know, here's the list of some automation testing tools that i think they are the best at this moment:

1. Testcomplete https://smartbear.com (It's a paid automation tool. It's an little tricky to learn and use but quite similar to Selenium)

2. Katalon Studio: https://www.katalon.com (It's a free automation tool - enhances Selenium and Appium with a complete test automation framework that helps you start testing in no time)

3. Tosca Testsuit: www.tricentis.com (There are many more features that are useful for automation but there can really be a need for some coding effort to integrate with your application)

And anything else?

Suggest few of the most preferred testing tools which are used to test apps based on REST APIs.

I am using selenium ide for finding the locators,here I got a locator 'link=History of *' which works in selenium ide but when I use the same locator in web driver code it fails.

Says " Unable to locate element: {"method":"link text","selector":"History of .*"} ".
Does selenium support regular expressions in its locators?

Please help me out in this.

It’s obvious that Smartphones are going to transform the world. Beginners in mobile app developing ought to know about the major challenges in mobile app testing. This will be a great help for Mobile App Testing Services. As a first time app developer I need to know about those challenges. Can anyone say the major challenges faced by Mobile App Testing Services?