Hi @KyleShriver ,
Could you please share a bit more about your scenario?
Do you want to find the App Id of the custom forms (created using PowerApps) in your SP list?
If you want to find the App Id of the custom forms (created using PowerApps) in your SP list, please take the following steps:
1. Edit your custom form in your SP list.
2. Wthin above opening custom form app, made some changes to it, e.g. add a Button control within your app, then delete it.
3. Click "File"-> "Save", then the "Publish to SharePoint" option and "See all versions" options would show up as below:
4. Within above step, click "See all versions" option. Within the opening page, click "Details" tab as below:
then you could see the App ID value there (as above).
Please also check and see if the follownig article would help in your scenario:
https://wonderlaura.com/2018/12/06/powerapps-standalone-app-versus-customized-list-form/
Best regards,