Best scalable website visitor communication tool I've found (with a free plan)

As a marketing agency, we use Tidio both for our own purposes, as well as our clients'. Website visitors these days have shorter attention spans and are accustomed to chat widgets that can give instant (or almost instant) answers. Even for my B2B clients who don't stay actively online with Tidio to personally answer inquiries, the chat widget generates leads and contacts from site visitors who are less inclined to fill out a traditional web form or send an email. Having multiple contact formats (phone, email, web form and chat) allows visitors to reach out via the channel they are most comfortable with, leaving less traffic to slip through the cracks.