Well, it's still Autumn, and there are plenty more Autumn poems to subject you to. Since Shelley's “Ode to the West Wind” is probably the next best after Keats, and since the whole thing is very long, here's the finale, which is really rather fine:
Make me thy lyre, even as the forest is:
What if my leaves are falling like its own!
The tumult of thy mighty harmonies
Will take from both a deep, autumnal tone,
Sweet though in sadness. Be thou, Spirit fierce,
My spirit! Be thou me, impetuous one!
Drive my dead thoughts over the universe
Like withered leaves to quicken a new birth!
And, by the incantation of this verse,
Scatter, as from an unextinguished hearth
Ashes and sparks, my words among mankind!
Be through my lips to unawakened earth
The trumpet of a prophecy! O Wind,
If Winter comes, can Spring be far behind?