From Creative Bloq, a list of free tools, mostly web-based, for creating infographics. A good range here, from data visualization to diagramming tools and templates.

I'm not a massive fan of the trend towards the indiscriminate use of infographics - it's much too easy to disguise shallow thinking and inadequate research, and way too easy to fail to pass along things that matter and emphasize things that don't, making them dangerous for much the same reasons as PowerPoint is dangerous - but, when they are done well, and when they are combined with links to richer sources of information, they can be powerful learning tools.