Here's how to do it.​

Open your lead list (that must contain all emails as one of its column) in Google sheets and do the following:

1: Copy the email column (let's say D) and paste it in an empty column (let's say H)


2: Select the D column > Right click > Choose “Smart Chips” > "Convert to People Chip"

Now you have a D column with all the valid emails in chips and non-valid or non G Suite emails in text.
It's time to filter out the valid emails from D columns.


3: Select the D column > Choose "Data" from top navigation > Choose "Create a Filter" > Choose "Filter by Condition" >
then scroll down to "Custom Formula is" > Now write "=NOT(D2=H2)" > Click on Ok and that's how you just filtered out all valid G Suite emails.




4: Now remove the H column and copy all the rows to your valid email list.


This works for G Suite emails