Minecraftuuid.com - This site is similar to NameMC with one important difference. It sometimes, but not always, gives you an account creation date.
This is important when you think a whitelist applicant might be lying about their age. For example, if they are much older than they claim to be. A user who is claiming to be 16, probably won’t have an account created in 2010 for example. Alone this is probably not proof of lying about their age as a parent may have created the account, or they may have purchased the account from someone else at a later date, but it could be included with other information as evidence if there are other items to back it up.
Example of an account with a created date