re: Anybody know how to find old 401ks?

It’s possible that it’s on your tax transcript. Likely not since it is generating taxable transactions, but I have seen the accounts on them. Create an IRS account, your transcripts are there.

That is assuming you can’t call the old plan admin (former employer that started the plan) to access your account. The employer is the sponsor and are obligated to keep the records.

If they terminated the plan, unclaimed property in the state the company was in.