Here’s a quick one-liner to fetch a list of all relying part trusts that use the SHA256 hashing algorithm.

Get-AdfsRelyingPartyTrust | Where {$_.SignatureAlgorithm -Like “http://www.w3.org/2001/04/xmldsig-more#rsa-sha256” | FT Name

If you want to get a list of all RPT’s using SHA1, replace the URL with “http://www.w3.org/2000/09/xmldsig#rsa-sha1”.

Hope this helps! :)