Hi @Anonymous ,
Do you want to collect the Attachments from your SP List into a collection?
Actually, it is a known issue within PowerApps app -- when collecting SP List records into a collection, it would not collect the Attachments column value from SP List.
Currently, If you want to collect the Attachments column value from your SP List into a collection, I afraid that there is no way to achieve your needs.
If you would like this feature to be added in PowerApps, please submit an idea to PowerApps Ideas Forum:
https://powerusers.microsoft.com/t5/Power-Apps-Ideas/idb-p/PowerAppsIdeas
As an alternative solution, you could consider add an nested Gallery inside your current existing Gallery, then set the Items property of the nested Gallery to following:
LookUp('Your SP List', ID = ThisItem.ID).Attachments
Set the Text property of the Label inside the nested Gallery to following:
ThisItem.DisplayName

If you want to download corresponding Attachment file from the nested Gallery, you could consider add a "Download" icon inside the nested Gallery, set the OnSelect property to following:
Download(ThisItem.AbsoluteUri)

Best regards,