I rely on the following software products to build up online assets (content sites, productized services etc) that can be sold. I can personally recommend any of these companies in terms of the amount of value they create and the support they give.
I use Elementor Pro to build CTA boxes such as on the productized services page or to design entire pages. You can get started for free with the basic version of the plugin but the pro version includes elements such as post grids and popups. I use Elementor on all of my sites now (replaced both Thrive Architect and Leadpages).
Gist is well-priced marketing automation software which also integrates live chat, forms and a knowledge base which gives the best 360° view of your contacts of any software I've used