1) Boundlessly 2) Colossally 3) Considerably 4) Enormously 5) Greatly 6) Hugely 7) Immeasurably 8) Immensely 9) Incalculably 10) Inestimably 11) Massively 12) Vastly 13) Without bounds 1) Boundlessly 2) Endlessly 3) Eternally 4) Hugely 5) Immeasurably 6) Unboundably 
• (adv.) Without bounds or limits; beyond or below assignable limits; as, an infinitely large or infinitely small quantity. • (adv.) Very; exceedingly; vastly; highly; extremely.
In'fi·nite·ly adverb 1. Without bounds or limits; beyond or below assignable limits; as, an infinitely large or infinitely small quantity. 2. Very; exceedingly; vastly; highly; extremely. ' Infinitely pleased.' Dryden. 
[adv] - continuing forever without end
endlessly adverb continuing forever without end; `there are infinitely many possibilities`