Hello and welcome to the forum.
The only plug-in you will find in AmpliTube 5. THe various gear mdoels are inside the plug-in and do not appear as separate plug-ins.
Double-check that AT5 is Registered and Authorized. If so, then run the new Custom Shop program (v2.something), log in, click on your User Account name and select "Restore my Purchases". Then try AT5 to see if the gear models are available for use.
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PS: it would be best to change your Account Name away from an email address, to minimise the chance of it being harvested by web bots and you receiving all sorts of 'special offers', bank account verification requests, Internet Disconnection notifications, Amazon Prime renewals, Ray-Ban sunglasses, tax refunds etc from all over the place for years and years. You can change it
here.