Starting from Tridion Docs 13SP1 you always need an existing Editor Template to be able to create content objects like Topics, Images, Maps, and Other. Typically they are there, the Other might be an issue. The below snippet gets you going of adding the first/initial one using the API through ISHRemote.

Add-FirstEditorTemplate.ps1

$ishSession = New-IshSession -WsBaseUrl "https://example.com/ISHWS/" -PSCredential "Admin"
# Manually create a folder of type 'Other' and provide it as FolderPath parameter
$otherIshFolder = Get-IshFolder -IshSession $ishSession -FolderPath "\System Management\Editor Templates\Other\"  # Please verify
# Below code creates an empty text file and creates your initial Other content object
Set-Content -Path "$env:TEMP\empty.txt" -Value "Empty Text File, or not" -Force
$metadata = Set-IshMetadataField -IshSession $ishSession -Level Logical -Name FTITLE -Value "Empty Template" | 
            Set-IshMetadataField -IshSession $ishSession -Name "FAUTHOR" -Level Lng -ValueType Element -Value VUSERADMIN |
            Set-IshMetadataField -IshSession $ishSession -Name "FSTATUS" -Level Lng -ValueType Element -Value VSTATUSDRAFT
Add-IshDocumentObj -IshSession $ishSession -IshFolder $otherIshFolder -IshType ISHTemplate -LogicalId ISHEDITORTEMPLATETXT -Metadata $metadata -Lng en -Edt "EDT-TEXT" -FilePath "$env:TEMP\empty.txt"
# Once the object is created, manually push it through the workflow as Editor Templates need to be (R)eleased before they show up