Only info I can give is to search in the GOG app, all the plus icons you see without a shopping cart can be added to your library for free, you can see the ones I already added as well:

:bc_happypaws: 1
Only info I can give is to search in the GOG app, all the plus icons you see without a shopping cart can be added to your library for free, you can see the ones I already added as well:
