Basically every unlimited wireless provider offers hotspot data, but Visible, Verizon, and AT&T offer up the most value based on cost, network coverage, data speed, and data allotment.
If you're willing to sacrifice internet speed in exchange for unlimited hotspot data, you should consider Visible's $40 Unlimited Plan. Visible's plan offers unlimited 5 Mbps data and reliable coverage, and it's about half the cost of both AT&T's and Verizon's plans. But you won't be able to stream or game at such a slow speed.
If reliable coverage matters most to you, then Verizon's Do More Unlimited is your best bet. But it's not a great deal considering Verizon's plan gives you only half the data as AT&T's but at almost the same price.
If you want lots of high-speed hotspot data and are willing to pay for it, AT&T's Unlimited Elite is the plan for you.