If you are looking for the best OST to PST Recovery third party tool then I will give you best solution you can try Stella OST to PST Recovery software. It is very easy method to recover all size of file and any types of errors. This software work very smoothly and support all version of Outlook PST file.
For More Information: https://medium.com/@stelladatarecovery/outlook-recovery-e6a907014dd2
See the process of Stella OST to PST Converter software: https://youtu.be/CSaLnzypSYY