How can I set account never locked out for just some users?

Computer Configuration\Windows Settings\Security Settings\Account Policies\Account Lockout Policy

Set the account threshold to 0 so the account will never be locked

You can create new GPO and apply it on specific users.

I recommend you carefully to read this article

https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/account-lockout-threshold#security-considerations

Hi there @Ahmed Abdelbaset, if your comment is the last one you can just use the Edit button and change your comment :)

About the question:
here's documentation directly from Microsoft:
https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/account-lockout-policy

I would add that you need to find out what is the reason to get all the accounts locked out, thinking in a malware  or virus attack that did a dictionary attack domain wide and blocked everybody and everyone's pc, so I think that the solution would be to ensure the security instead of open the little security that is left on the site...

I mean that you apply policy on OU have computers that users logon to with using GPO Security filtering to limit  that policy applying for specific user or users group.

Is that clear ?

@Ahmed, your solution would only work for local accounts. Uniqie domain account policies require fine grained password policies since all domain accounts live on the domain controllers.

Yes, Fine grained password would be ideal if you lockout password needed for different set of users.

However it's not recommend from security presective to set account lockout policy threshold value to 0.

However it's not recommend from security presective to set account lockout policy threshold value to 0.

Not really. Microsoft best practice is 0 if you have a system to monitor bad logons and 50 otherwise.
You cannot protect against a DDoS and a brute-force simultaneously.
 https://www.experts-exchange.com/articles/29305/Active-Directory-Locked-Account-Investigation-Process.html

Fine grain password policy is the only option

Thanks!