What's this?! In a surprisingly consumer-friendly move, Sony has confirmed that select PS1 and PSP games will be available separately as part of the new PS Plus Premium Tier. This means you can purchase them directly from the PS Store even though you don't wish to subscribe. You can also download any digital games you have from the past (such as PS3 and PSP) for free.
This kind of legacy support is normal for digital storefronts. However, this generosity was something we didn't expect from Sony in this age. Many of these classic titles will now be enhanced by a new user interface that incorporates modern quality-of-life features such as save states and rewind. This is truly refreshing.
Are you going to be digging into classics from day one? The link will take you to a list all PS Plus games.