If you elminate the shady claims of so many MVNOs who claim unlimited data , but then throttle you to a barely usable 128 kbps , or the very few who throttle to a completely unusable 64 kbps. these are the only choices (unless you jump to a $50 price point plus taxes).
Truly unlimited LTE data:
-Visible @ $25 with no taxes on Verizon
-Metro @ $25 with no taxes on T-Mobile
-Cricket @ $30 with no taxes on AT&T (only with one year paid up front)
(And it must be noted , only Visible offers free unlimited HotSpot , but with clearly defined, but quite reasonable restrictions, IMHO)
(And it must be further noted that both Visible and Metro are better deals than the multi line deals offered by other MVNOs , given that the multi line deals add taxes)
And the next closet option to all of the above is at @ $50 plus taxes (Total by Verizon and T-Mobile prepaid) .
( source: prepaidcompare, and a bit of my own own research)