Queries SQL Server, and uses the HTML that it produced and pastes it to teams.

teams_posting_sql_as_table.ps1

<#you can't use ACTUAL adapter cards, but you can use HTML, albeit just BODY.#>
<#Thebakingdba.blogspot.com 2019#>
. C:\Powershell_Scripts\invoke-sqlcmd2.ps1 

$query = @"

DECLARE @tableHTML NVARCHAR(MAX)
  ,   @MailSubject VARCHAR(200)

SELECT @tableHTML = '<table>'
            + N'<th>database_id</th>'
            + N'<th>db_name</th>'
            + N'<th>create_date</th>'
            + N'<th>recovery_model</th>'
            + N'<th>recovery_model_desc</th>'
            + CAST(( 
				SELECT top 5 
                          td = ISNULL(CONVERT(VARCHAR(20),database_id),'')
				, ''	, td = ISNULL(name,'')
				, ''	, td = ISNULL(CONVERT(VARCHAR(20),create_date,120),'')
				, ''	, td = CONVERT(VARCHAR(1),recovery_model)
				, ''	, td = CONVERT(VARCHAR(60),recovery_model_desc)
		FROM    sys.databases
		ORDER BY database_id
      FOR      XML PATH('tr') , TYPE ) AS NVARCHAR(MAX)) + N'</table>' ;

SELECT @tableHTML as tablehtml
"@

$queryresults = Invoke-Sqlcmd2 -ServerInstance myservername -Database mydbname -query $query

$webhook_URL = "https://outlook.office.com/webhook/......"

$json = @"
{
  "$schema": "http://adaptivecards.io/schemas/adaptive-card.json",
  "text": "$($queryresults.tablehtml)",
  "version": "1.0",
  "type": "AdaptiveCard"
}
"@

Invoke-RestMethod -Method post -ContentType 'Application/Json' -Body $json -Uri $webhook_URL